Dinner

Watercress Soup with Peas and Mint (Princess Diana Recipe)

This elegant soup is basically royalty in a bowl, and you don’t need a palace kitchen to pull it off perfectly.

The combination of peppery watercress, sweet peas, and fresh mint creates a flavor profile that’s both sophisticated and surprisingly comforting.

What makes this recipe truly special is how the bright green vegetables maintain their vibrant color and fresh taste through the gentle cooking process.

The creamy Greek yogurt garnish adds a tangy richness that balances the earthiness of the watercress beautifully.

Those golden homemade croutons provide the perfect textural contrast to the silky smooth soup base.

Best of all, this impressive dish comes together in just 35 minutes, making it perfect for both weeknight dinners and elegant entertaining.

Ingredients

For the Croutons

2 thick slices country bread
1 tablespoon extra virgin olive oil
Kosher salt to taste
Freshly ground pepper to taste

For the Soup

8 cups (10 ounces) fresh watercress
2 tablespoons extra virgin olive oil
1 cup sliced leeks, white and light green parts only
Kosher salt to taste
Fresh ground pepper to taste
2 cups chicken stock, homemade or quality low-sodium store bought
2 cups (10 ounces) frozen peas
Zest of one lemon
1 /2 cup Greek yogurt
1 tablespoon fresh lemon juice
1 /2 cup fresh mint leaves, firmly packed, plus extra for serving

Instructions

Preparation

1 Preheat your oven to 375°F (190°C). This moderate temperature ensures the croutons become golden and crispy without burning.
2 Tear the bread into roughly bite-sized pieces (about 2 cups total) and add to a large mixing bowl. Add 1 tablespoon olive oil and season generously with kosher salt and freshly ground pepper. Toss well to coat every piece evenly, then transfer to a rimmed baking sheet and spread in a single layer. Bake until croutons are golden brown, shaking the pan once halfway through, about 10 minutes. Set aside to cool completely – this prevents them from becoming soggy when added to the soup.
3 Remove the thick stems from the watercress and place the leaves in a salad spinner. Cover with cold water and let sit until the greens look crisp and refreshed, about 5 minutes. This step ensures maximum freshness and removes any grit. Drain thoroughly, spin dry, and roughly chop into manageable pieces.

Cooking the Soup Base

4 In a large pot or Dutch oven, heat 2 tablespoons olive oil over medium-low heat until shimmering. Add the sliced leeks and season with a generous pinch of salt and pepper. Cook, stirring occasionally with a wooden spoon, until leeks are completely softened and translucent, about 10 minutes. Don’t rush this step – properly cooked leeks provide the sweet, aromatic foundation for the soup.
5 Add the chicken stock and 1 1/2 cups water to the pot. Turn the heat to high and bring to a rolling boil, then immediately reduce heat to low. Add the frozen peas and chopped watercress to the simmering liquid. Cover and simmer gently until the peas are completely tender and the watercress has wilted, about 5 minutes.

Creating the Garnish

6 While the soup simmers, prepare the yogurt garnish in a small mixing bowl. Combine the Greek yogurt and fresh lemon juice, then season generously with salt and freshly ground pepper. Whisk vigorously until the mixture is smooth and pourable – if your yogurt is particularly thick, add a splash of water to achieve the right consistency.

Finishing and Serving

7 Remove the soup from heat and immediately stir in the fresh mint leaves just until they wilt from the residual heat. Working in batches if necessary, transfer the soup to a high-speed blender. Leave a gap at the top and remove the steam cap, starting on low speed and gradually increasing to prevent hot liquid from splashing. Purée until completely smooth and vibrant green.
8 Taste and adjust seasoning with salt and pepper. If the soup seems too thick, thin with up to 1/2 cup water until you reach your preferred consistency. For hot service, return to the pot and gently reheat over medium-low heat. For cold service, cool completely, cover, and refrigerate for at least 1 hour along with the yogurt garnish.
9 Serve immediately, garnishing each bowl with golden croutons, a generous dollop of the lemon yogurt sauce, and a few fresh mint leaves for color and aroma.

Recommended Equipment and Kitchen Tools

Essential Tools (for best results):

Salad spinner – Crucial for properly cleaning and drying the watercress, which can harbor grit and excess moisture that would dilute the soup’s flavor
High-speed blender – Creates the silky smooth texture that makes this soup restaurant-quality; an immersion blender works but won’t achieve the same velvety consistency
Large Dutch oven or heavy-bottomed pot – Ensures even heat distribution when sautéing the leeks and prevents scorching during the simmering process
Rimmed baking sheet – Essential for making evenly golden croutons that won’t roll off during baking

Helpful Upgrades:

Kitchen scale – For precise measurement of the watercress and peas, ensuring consistent results every time you make this recipe
Microplane grater – Creates perfectly fine lemon zest that distributes evenly throughout the soup without bitter pith
Fine-mesh strainer – Optional but helpful for achieving an ultra-smooth soup texture by straining after blending

Nice-to-Have Options:

Mandoline slicer – Makes quick work of slicing leeks to uniform thickness for even cooking
Silicone spatula – Perfect for scraping every bit of soup from the blender and ensuring nothing goes to waste
Ladle with pour spout – Makes elegant presentation easier when serving the soup into individual bowls

Recipe Variations and Dietary Modifications

Vegan Adaptation:

Replace chicken stock with high-quality vegetable stock or mushroom broth for deeper umami flavor
Substitute Greek yogurt with cashew cream or coconut yogurt for the garnish
Add a tablespoon of nutritional yeast to enhance the savory depth
Consider adding a splash of white wine to the leeks for extra complexity

Dairy-Free Modifications:

Use coconut yogurt or cashew-based yogurt for the garnish – coconut yogurt provides richness while cashew yogurt offers neutral flavor
Ensure your chosen stock is dairy-free, as some commercial stocks contain milk derivatives
Drizzle with high-quality extra virgin olive oil instead of yogurt for richness

Protein Boost Variations:

Stir in cooked white beans or cannellini beans before blending for added protein and fiber
Top with poached egg or soft-boiled egg for a more substantial meal
Add cooked chicken or turkey for a heartier soup

Seasonal Flavor Variations:

Spring version: Add fresh asparagus tips and chives along with the peas
Summer version: Include fresh basil along with the mint for an herbal twist
Fall version: Add a touch of fresh thyme and roasted garlic for warmth
Winter version: Include a pinch of white pepper and fresh parsley

Texture Variations:

Leave some soup unblended for a rustic, chunky texture
Blend only half the soup and combine for varied mouthfeel
Add cooked quinoa or rice for substance

Nutritional Information and Health Benefits

Key Nutritional Highlights:
This soup provides approximately 180 calories per serving while delivering exceptional nutritional density. Each bowl contains roughly 8 grams of plant-based protein from the peas and watercress, 12 grams of fiber for digestive health, and 6 grams of healthy fats from the olive oil. The combination of vegetables provides significant amounts of vitamin K, vitamin C, folate, and iron.

Health Benefits of Main Ingredients:
Watercress stands out as one of the most nutrient-dense vegetables available, containing more vitamin C than oranges and providing powerful antioxidants like beta-carotene and lutein. The peppery greens also contain glucosinolates, compounds that support liver detoxification. Peas contribute plant-based protein, B vitamins, and antioxidants that support eye health. Fresh mint aids digestion and provides menthol compounds with anti-inflammatory properties. The leeks offer prebiotic fiber that supports gut health, while Greek yogurt provides probiotics and calcium for bone health.

Dietary Considerations:
This soup is naturally gluten-free (excluding the bread croutons), vegetarian-friendly, and low in saturated fat. It’s particularly rich in folate, making it beneficial for pregnant women, and the high vitamin K content supports bone health. The combination of fiber and protein helps maintain stable blood sugar levels, while the anti-inflammatory compounds from the herbs and vegetables support overall wellness.

Smart Swaps and Ingredient Substitutions

Common Substitutions:

Watercress → Arugula or baby spinach (use same amount, though flavor will be milder)
Fresh peas → Frozen peas work perfectly; fresh peas need 2-3 minutes longer cooking time
Leeks → Yellow onion (use 1/2 cup diced) or green onions (white parts only)
Greek yogurt → Sour cream, crème fraîche, or coconut yogurt for dairy-free option
Fresh mint → Fresh basil or parsley, though mint provides the signature flavor

Budget-Friendly Swaps:

Country bread → Any day-old bread works for croutons; even sandwich bread crisps up nicely
Homemade stock → Quality low-sodium boxed stock saves time without sacrificing flavor
Fresh herbs → Use 1/3 the amount of dried herbs if fresh aren’t available
Extra virgin olive oil → Regular olive oil for cooking (save EVOO for finishing)

Pantry Emergency Substitutions:

No salad spinner → Wash watercress in cold water, drain well, and pat dry with paper towels
No blender → Use immersion blender directly in pot, though texture won’t be as smooth
No leeks → Substitute with 1/2 cup finely diced sweet onion
No fresh lemon → Use 2 teaspoons bottled lemon juice, though fresh is preferred

Pro Tips for Substitutions:

Store leftover watercress wrapped in damp paper towels in the refrigerator for up to 5 days
Frozen peas often have better flavor than out-of-season fresh peas
When substituting herbs, add delicate ones like basil at the very end to preserve flavor

Make It Diabetes-Friendly

Carb Reduction Strategies:

Skip the bread croutons and use toasted nuts like almonds or walnuts for crunch (saves 15g carbs per serving)
Reduce peas to 1 cup instead of 2 cups (saves 8g carbs per serving)
Use full-fat Greek yogurt instead of low-fat versions to increase satiety and slow carb absorption

Portion & Blood Sugar Management:

Recommended serving size: 1 cup soup with 2 tablespoons yogurt garnish
Estimated carbs per serving: Approximately 12-15 grams with modifications
Pair with protein: Add 2-3 ounces cooked chicken or 1/4 cup nuts to create a more balanced meal
Timing tip: Consume as a starter before protein-rich main course to help moderate blood sugar response

Enhanced Nutrition Modifications:

Add fiber: Include 1 tablespoon ground flaxseed when blending for extra fiber and omega-3s
Increase healthy fats: Drizzle with 1 teaspoon extra virgin olive oil per serving
Boost protein: Stir in 1/4 cup cooked white beans before blending

Total Carb Reduction: These modifications reduce carbs by approximately 20-25 grams per serving compared to the original recipe while maintaining the essential flavors and satisfaction.

Perfect Pairing Suggestions

Beverage Pairings:
A crisp Sauvignon Blanc or Pinot Grigio complements the fresh, herbaceous flavors beautifully, while the wine’s acidity enhances the soup’s bright character. For beer lovers, a Belgian witbier or light pilsner provides refreshing contrast. Non-alcoholic options include sparkling water with cucumber and mint, green tea, or fresh lemonade that echoes the soup’s citrus notes. The elegant nature of this soup also pairs wonderfully with champagne or prosecco for special occasions.

Side Dish Recommendations:
Crusty sourdough bread or herb focaccia makes an ideal accompaniment for dipping and adds satisfying substance. A simple arugula salad with lemon vinaigrette provides textural contrast while maintaining the fresh, peppery theme. Grilled asparagus or roasted spring vegetables complement the seasonal nature of this soup. For a more substantial meal, serve alongside herb-crusted salmon or lemon chicken that won’t compete with the delicate flavors.

Complete Meal Ideas:
Start with this soup as an elegant first course, followed by pan-seared fish with herbs, roasted chicken thighs, or quinoa-stuffed bell peppers for vegetarian guests. The meal flows beautifully into lemon panna cotta or fresh berry tart for dessert. For casual entertaining, serve the soup as the main course with artisanal bread, cheese selection, and seasonal fruit for a sophisticated yet relaxed meal.

Occasion Suggestions:
This soup shines at spring dinner parties, Easter brunch, Mother’s Day celebrations, or any time you want to create an impression of effortless elegance. It’s perfect for al fresco dining and garden parties where the fresh, vibrant flavors complement outdoor settings beautifully.

Pro Tips and Troubleshooting

Professional Techniques:
Blanch and shock method: For even brighter color, blanch the watercress in boiling salted water for 30 seconds, then immediately plunge into ice water before proceeding with the recipe. This technique locks in the vibrant green color. Temperature control is crucial – never let the soup boil vigorously once the greens are added, as this can cause the color to dull and the texture to become stringy.

Common Mistakes and Solutions:
Gritty texture: Always wash watercress thoroughly in multiple changes of cold water, as it can harbor sand and dirt. Bitter flavor: Remove thick stems completely, as they contribute unwanted bitterness. Dull color: Add greens to already-hot liquid and don’t overcook – 5 minutes maximum maintains vibrant color. Thin consistency: Reserve some cooking liquid before blending, then add back gradually to achieve desired thickness.

Storage and Make-Ahead Strategies:
This soup keeps beautifully in the refrigerator for up to 3 days and actually improves in flavor as the herbs meld. Freeze for up to 3 months, though the texture may be slightly less smooth after thawing. Make the yogurt garnish separately and store covered. Reheat gently over low heat, stirring frequently to prevent separation. The croutons can be made 2 days ahead and stored in an airtight container.

Scaling and Presentation Tips:
This recipe doubles easily for entertaining – use a large stockpot and blend in batches. For elegant presentation, warm serving bowls in a low oven, drizzle yogurt in artistic patterns, and garnish with microgreens or edible flowers for special occasions.

This Princess Diana-inspired soup proves that royal-worthy cuisine doesn’t require complicated techniques or exotic ingredients – just quality ingredients treated with care and respect. The vibrant flavors and elegant presentation make every bowl feel like a special occasion, whether you’re serving family dinner or entertaining guests. With its perfect balance of fresh herbs, creamy texture, and satisfying crunch from the homemade croutons, this soup embodies the timeless appeal of simple, seasonal cooking done exceptionally well.