Kentucky Hot Brown Casserole with Mornay Sauce

This Kentucky Hot Brown Casserole is basically comfort food royalty masquerading as a weeknight dinner – and honestly, we’re not mad about it.

Picture this: golden cubes of toasted sourdough bread getting cozy with tender turkey and crispy bacon, all swimming in the most luxurious, cheese-laden Mornay sauce that’ll make you question every other casserole you’ve ever made.

The cherry tomatoes burst with juicy sweetness against the rich, creamy backdrop, while that freshly grated Parmesan creates the kind of golden, bubbly top that makes you want to take a photo before anyone digs in.

What makes this version absolutely genius is how it transforms the classic Kentucky Hot Brown sandwich into a make-ahead casserole that feeds a crowd without requiring you to toast individual pieces of bread or worry about perfect plating.

The Mornay sauce – which is basically a fancy white sauce with cheese that sounds way more intimidating than it actually is – coats every single bite with velvety richness that’ll have people asking for the recipe before they’ve even finished eating.

This is the kind of dish that makes you look like a culinary mastermind while secretly being straightforward enough that you can make it on a Tuesday without breaking a sweat.

Ingredients

For the Mornay Sauce

• 8 tablespoons butter
• ⅓ cup all-purpose flour
• 1½ cups heavy cream
• 1½ cups whole milk
• ½ teaspoon salt
• ½ teaspoon black pepper
• ¼ teaspoon nutmeg
• ¼ teaspoon smoked paprika
• 8 ounces Parmesan cheese – freshly shredded and divided in half

For the Casserole

• 6-8 cups sourdough bread (roughly one loaf) – cubed and toasted
• 3 cups cooked turkey breast – cubed
• 8-9 pieces bacon – cooked and crumbled
• 1 cup cherry tomatoes – diced
• Fresh parsley – minced for garnish

Instructions

Preparation

1. 1 Preheat your oven to 350°F (175°C). Spread the cubed sourdough bread on a large baking sheet in a single layer and toast for 15 minutes while you prepare the Mornay sauce. The bread should be golden and slightly crispy on the outside but still tender inside – this prevents it from getting soggy in the casserole.

Make the Mornay Sauce

1. 2 Add 8 tablespoons butter to a large, heavy-bottomed saucepan and melt over medium heat. Using a heavy-bottomed pan prevents hot spots that could cause the sauce to curdle or burn.
2. 3 Add the ⅓ cup flour and whisk vigorously to combine. Cook this roux for 2-3 minutes, whisking constantly to eliminate the raw flour taste. The mixture should bubble gently and smell nutty, not burn.
3. 4 Reduce heat to medium-low and slowly pour in the heavy cream about ½ cup at a time, whisking continuously between each addition. This gradual process prevents lumps from forming and ensures a silky smooth sauce. Add the whole milk and whisk again until completely smooth.
4. 5 Add the salt, black pepper, nutmeg, and smoked paprika, stirring to combine. Cook for 5 minutes, whisking frequently as the sauce thickens to coat the back of a spoon. The sauce should be thick enough to coat pasta but still pourable.
5. 6 Remove from heat and whisk in half of the shredded Parmesan cheese (about 4 ounces). The residual heat will melt the cheese perfectly. Set aside for assembly.

Prep the Remaining Ingredients

1. 7 Cube the cooked turkey breast into bite-sized pieces, roughly ¾-inch cubes.
2. 8 Crumble the cooked bacon into chunky pieces – not too fine, as you want texture in every bite.
3. 9 Dice the cherry tomatoes into quarters, removing excess seeds if they’re particularly juicy.
4. 10 Mince the fresh parsley for garnish and set aside.

Assembly and Baking

1. 11 Grease a 9×13-inch baking dish with non-stick cooking spray or butter, ensuring all corners are well-coated.
2. 12 Spoon about ⅓ of the Mornay sauce into the bottom of the prepared dish, spreading it evenly. Add half of the toasted bread cubes on top, distributing them evenly.
3. 13 Layer the ingredients in this specific order: half of the cubed turkey, half of the crumbled bacon, another third of the Mornay sauce, remaining bread cubes, remaining turkey, remaining bacon, and finally the last of the sauce as the top layer. This layering ensures every bite has the perfect ratio of ingredients.
4. 14 Sprinkle the remaining Parmesan cheese evenly over the top, then distribute the diced cherry tomatoes across the surface. The tomatoes will burst slightly during baking, adding fresh acidity to cut through the richness.
5. 15 Bake for 25-30 minutes until the top is golden brown and the sauce is bubbling around the edges. The internal temperature should reach 165°F (74°C) when tested with an instant-read thermometer.
6. 16 Remove from oven and let cool for 5-10 minutes before serving. This resting time allows the sauce to set slightly, making it easier to serve. Garnish with fresh minced parsley and serve immediately.

Recommended Equipment and Kitchen Tools

Essential Tools (for best results)

• Large heavy-bottomed saucepan – Prevents the Mornay sauce from scorching and ensures even heat distribution for smooth, lump-free results
• Wire whisk – Crucial for creating the silky Mornay sauce and preventing lumps when incorporating the cream and milk
• 9×13-inch baking dish – The ideal size for proper layering and even cooking of this casserole
• Instant-read thermometer – Ensures the casserole reaches the safe internal temperature of 165°F (74°C)

Helpful Upgrades

• Kitchen scale – For precise measurements of flour and cheese, leading to more consistent sauce texture
• Microplane grater – Freshly grated Parmesan melts more smoothly than pre-shredded and creates a better sauce
• Silicone spatula – Perfect for scraping every bit of that precious Mornay sauce from the pan
• Parchment paper – Makes cleanup easier when toasting the bread cubes

Nice-to-Have Options

• Stand mixer with whisk attachment – Can help incorporate the cream more efficiently for larger batches
• Mandoline slicer – Creates perfectly uniform bread cubes if you’re slicing your own sourdough
• Glass measuring cups – Easier to see liquid levels when gradually adding cream to the roux

Recipe Variations and Dietary Modifications

Gluten-Free Adaptation

• Replace all-purpose flour with ⅓ cup gluten-free flour blend (1:1 ratio works perfectly)
• Substitute gluten-free bread for the sourdough – day-old gluten-free sandwich bread works well
• Expect slightly different texture in the sauce, but flavor remains excellent
• May need an extra 2-3 minutes of cooking time for the gluten-free roux

Dairy-Free Modifications

• Replace butter with vegan butter or olive oil (use 6 tablespoons oil)
• Substitute heavy cream with full-fat coconut milk and whole milk with unsweetened oat milk
• Use nutritional yeast (about ½ cup) instead of Parmesan for cheesy flavor
• Add extra salt and garlic powder to enhance flavor depth

Protein Variations

• Leftover chicken works beautifully in place of turkey
• Ham and turkey combination creates a more traditional Hot Brown flavor
• Vegetarian version: Replace turkey with roasted mushrooms and extra cheese
• Seafood twist: Use cooked shrimp or crab meat for an elegant variation

Flavor Enhancements

• Add sautéed mushrooms between layers for earthy depth
• Include caramelized onions for sweetness and complexity
• Incorporate fresh thyme or rosemary into the Mornay sauce
• Top with buttery breadcrumbs mixed with Parmesan for extra crunch

Nutritional Information and Health Benefits

Key Nutritional Highlights

This Kentucky Hot Brown Casserole provides approximately 485 calories per serving when cut into 8 portions. The combination of turkey, cheese, and bread creates a well-balanced macronutrient profile with roughly 28 grams protein, 18 grams fat, and 35 grams carbohydrates per serving. The heavy cream and Parmesan contribute significant calcium content, while the turkey provides lean protein and essential amino acids.

Health Benefits of Main Ingredients

Turkey breast is an excellent source of lean protein, providing all essential amino acids while being lower in saturated fat than many other proteins. It’s rich in selenium, which supports immune function, and B vitamins that aid in energy metabolism. Parmesan cheese offers concentrated calcium and protein, plus beneficial probiotics if you choose aged varieties. The cherry tomatoes contribute lycopene, a powerful antioxidant that becomes more bioavailable when cooked, along with vitamin C and potassium. Sourdough bread provides easier digestibility compared to regular bread due to its fermentation process, which breaks down some of the gluten and phytic acid.

Dietary Considerations

This recipe contains gluten, dairy, and is high in sodium due to the cheese and bacon. It’s suitable for those following a Mediterranean-style diet when paired with a large salad. The high protein content makes it satisfying and helps maintain stable blood sugar levels. For optimal nutrition, serve with steamed vegetables or a mixed green salad to increase fiber and micronutrient density.

Smart Swaps and Ingredient Substitutions

Common Substitutions:

• Heavy cream → Half-and-half plus 2 tablespoons butter (reduces calories while maintaining richness)
• Whole milk → 2% milk or unsweetened almond milk (for lighter version)
• Sourdough bread → French bread, brioche, or day-old dinner rolls (similar texture and absorption)
• Turkey breast → Rotisserie chicken, leftover ham, or cooked chicken thighs (use what you have)

Budget-Friendly Swaps:

• Fresh Parmesan → Pre-shredded Parmesan (though fresh melts more smoothly)
• Cherry tomatoes → Diced canned tomatoes, drained (available year-round)
• Heavy cream → Evaporated milk (creates similar richness at lower cost)
• Bacon → Turkey bacon or ham pieces (more affordable protein options)

Pantry Emergency Substitutions:

• Nutmeg → Pinch of cinnamon or omit entirely (flavor will be slightly different)
• Smoked paprika → Regular paprika plus pinch of garlic powder (maintains color and mild flavor)
• Fresh parsley → Dried parsley (use 1 tablespoon dried instead of fresh)
• Cherry tomatoes → Sun-dried tomatoes, chopped (adds concentrated flavor)

Pro Tips for Substitutions:

• When using pre-shredded cheese, toss with 1 tablespoon cornstarch to prevent clumping in the sauce
• If using frozen bread cubes, thaw completely and pat dry before toasting to prevent sogginess

Make It Diabetes-Friendly

Carb Reduction Strategies:

• Replace sourdough bread → Cauliflower florets or zucchini slices (reduces carbs by approximately 25 grams per serving)
• Reduce bread to 4 cups → Add extra turkey and vegetables to maintain volume
• Use almond flour → 2 tablespoons almond flour instead of regular flour for the roux (saves 6 grams carbs per serving)

Portion & Blood Sugar Management:

• Recommended serving size: 1 cup portion provides approximately 28 grams carbohydrates
• Pair with: Large mixed green salad and steamed broccoli to add fiber and slow glucose absorption
• Timing tip: Consume with lean protein appetizer like turkey roll-ups to help stabilize blood sugar response

Enhanced Nutrition Modifications:

• Add fiber: Include 1 cup steamed broccoli or spinach between layers
• Increase protein: Use 4 cups turkey instead of 3 cups to improve satiety
• Smart fat additions: 2 tablespoons chopped walnuts provide healthy omega-3s without significant carb impact

Total Carb Reduction: These modifications can reduce carbohydrates from 35 grams to approximately 18 grams per serving while maintaining satisfying flavor and texture.

Perfect Pairing Suggestions

Beverage Pairings

A crisp Chardonnay or Sauvignon Blanc cuts beautifully through the rich Mornay sauce, while the wine’s acidity complements the cherry tomatoes. For beer lovers, a Belgian wheat beer or light lager provides refreshing contrast without overwhelming the delicate turkey flavors. Sparkling water with lemon or unsweetened iced tea offer non-alcoholic options that cleanse the palate between bites.

Side Dish Recommendations

Arugula salad with lemon vinaigrette provides peppery freshness that balances the casserole’s richness, while roasted Brussels sprouts with bacon echo the smoky flavors without competing. Steamed asparagus adds elegant color and crisp texture, and cranberry sauce brings tart sweetness that’s traditional with turkey dishes. Garlic roasted green beans contribute vibrant color and satisfying crunch.

Complete Meal Ideas

Start with spinach and strawberry salad as a light appetizer, serve the casserole as the main course alongside honey-glazed carrots, and finish with bourbon pecan pie for a complete Southern-inspired feast. For casual entertaining, pair with cornbread muffins and coleslaw for a comforting family-style meal.

Occasion Suggestions

Perfect for holiday brunches, potluck dinners, and Sunday family gatherings. The make-ahead nature makes it ideal for entertaining guests or meal prep Sundays. Elegant enough for Easter dinner yet comforting enough for weeknight family meals.

Pro Tips and Troubleshooting

Professional Sauce Techniques

The key to perfect Mornay sauce is temperature control – keep the heat at medium-low once you add the cream to prevent curdling. If your sauce does break, remove it from heat immediately and whisk in 1 tablespoon cold butter to re-emulsify. Strain the finished sauce through a fine-mesh sieve if you notice any lumps, and always add cheese off the heat to prevent it from becoming stringy.

Make-Ahead Strategies

Assemble the entire casserole up to 24 hours ahead, cover tightly with plastic wrap, and refrigerate. Add an extra 10-15 minutes to the baking time if cooking from cold. The Mornay sauce can be made 2 days ahead and reheated gently with a splash of milk to restore consistency. Freeze assembled casserole for up to 3 months – thaw overnight in refrigerator before baking.

Storage and Reheating

Store leftovers covered in refrigerator for up to 4 days. Reheat individual portions in microwave at 50% power for 2-3 minutes, stirring halfway through. For larger portions, cover with foil and reheat in 325°F (163°C) oven for 20-25 minutes until heated through. Add a splash of milk if the sauce seems too thick after reheating.

Scaling and Presentation

Double the recipe easily by using two 9×13-inch pans or one large roasting pan. For elegant presentation, garnish with fresh thyme sprigs and extra cherry tomato halves. Individual ramekins create beautiful single servings for dinner parties – reduce baking time to 15-20 minutes.

This Kentucky Hot Brown Casserole transforms a beloved regional sandwich into a crowd-pleasing casserole that’s perfect for everything from holiday entertaining to cozy family dinners. The combination of tender turkey, crispy bacon, and that absolutely divine Mornay sauce creates a dish that’s both comforting and sophisticated – exactly what you need when you want to impress without the stress.