Mom’s Scalloped Potatoes Gratin

Let me just put this out there – these aren’t just any scalloped potatoes. These are the kind that make people fall silent at the dinner table because they’re too busy closing their eyes and savoring each creamy, cheesy bite. The kind that have your family “casually” asking if you’re making them again next Sunday. The kind worth fighting over leftovers for.

What makes these potatoes magical is the perfect balance of textures – tender slices of gold potatoes layered with sweet onions, all bathed in a velvety cheese sauce that bubbles up around the edges. Then there’s that irresistible golden crust on top where the gruyere and parmesan get all toasty and create those crispy bits everyone fights over. This is comfort food elevated to an art form.

Ingredients

• 6-7 medium yukon gold potatoes, thinly sliced into 1/8th inch rounds (3 pounds gold potatoes — by weight is a more accurate measure)
• ½ white or yellow onion, cut into slices

For the sauce:

• 2 tablespoons salted butter
• ¼ cup all purpose flour (whole wheat, all purpose, or gluten free 1:1 flour will all work)
• 1 ½ cups unsweetened almond milk (regular, skim or whole milk will also work)
• 8 ounces sharp cheddar cheese (2 heaping cups shredded cheddar cheese)
• ½ teaspoon garlic powder
• ¾ teaspoon salt, plus more to taste
• Freshly ground black pepper

For topping:

• ½ cup gruyere cheese (or sub more sharp cheddar)
• ¼ cup grated parmesan

To garnish:

• Fresh chopped parsley

Steps

1. Preheat your oven to 375°F (190°C). Spray a 2-quart square baking dish (or an 8×12 dish) with nonstick cooking spray or grease thoroughly with butter. A proper coating prevents the potatoes from sticking during the long bake time.
2. Arrange sliced potatoes in three tight slanted rows in your prepared dish. The key is finding the perfect spacing – not too tight where they’re stacked directly on top of each other, but slanted with a slight overlap like fallen dominoes. This arrangement allows the sauce to flow between each slice for even cooking.

• Pro tip: Using a mandoline for slicing ensures uniform thickness, which means even cooking throughout.
• If cutting by hand, aim for consistent ⅛-inch thickness – any thicker and they won’t cook through properly.

1. Tuck onion slices between the potato rows and on top wherever they’ll fit. Don’t worry about perfect placement – the onions will soften and almost melt into the dish, adding subtle sweetness throughout.
2. Make your cheese sauce: In a medium saucepan, melt 2 tablespoons butter over medium heat. Once completely melted and starting to bubble slightly (but not brown), begin the roux:

• Add about 1 tablespoon of flour while whisking constantly.
• Immediately begin adding the milk ¼ cup at a time, alternating with remaining flour.
• Whisk vigorously after each addition until completely smooth before adding more – this prevents lumps from forming.
• The entire process should take 3-4 minutes.

1. Bring the mixture to a gentle simmer where small bubbles appear around the edges. The sauce should coat the back of a spoon and have a consistency similar to creamy gravy. If it seems too thick, add an additional 1-2 tablespoons of milk.
2. Reduce heat to low and stir in the shredded cheddar cheese, adding it gradually in three batches rather than all at once. This prevents the sauce from becoming grainy. Then add ½ teaspoon garlic powder, ¾ teaspoon salt, and ¼ teaspoon black pepper (or to taste).

• Take a small taste and adjust seasonings if needed – the sauce should taste slightly saltier than you think necessary as the potatoes will absorb some of the salt.

1. Pour the cheese sauce evenly over the potatoes and onions, making sure to get some between the potato slices. The sauce might look thin now, but it will thicken beautifully while baking.
2. Cover the dish tightly with aluminum foil and bake for 45 minutes. The foil traps steam, which helps cook the potatoes through without drying out the top.
3. After 45 minutes, carefully remove the foil (watch for hot steam) and sprinkle the top evenly with ½ cup gruyere (or additional cheddar) and ¼ cup parmesan cheese.
4. Return the uncovered dish to the oven and bake for an additional 30-45 minutes until deeply golden brown on top and bubbling around the edges. The potatoes should be fork-tender when pierced in the center – if you meet resistance, they need more time.
   • For extra browning in the final 5 minutes, you can switch to the broiler setting, but watch carefully to prevent burning.
5. Remove from the oven and let stand for 10-15 minutes before serving. This resting period allows the sauce to set slightly so it won’t run all over the plate. Garnish with fresh chopped parsley for a pop of color and fresh flavor.

Smart Swaps

• Replace almond milk with chicken broth (use 1¼ cups instead of 1½) for a lighter but still creamy sauce
• Substitute sweet potatoes for half the regular potatoes for a nutritional boost and beautiful color contrast
• Use smoked gouda instead of gruyere for a delicious smoky twist that pairs wonderfully with the sharp cheddar
• Add 1 tablespoon of fresh thyme leaves to the cheese sauce for an aromatic herb note

Make It Diabetes-Friendly

• Use rutabaga or turnip slices for ⅓ of the potatoes to reduce carbs by approximately 12g per serving
• Replace regular milk with unsweetened almond milk (already in recipe) to save 6g carbs per serving
• Add ½ teaspoon xanthan gum to the sauce instead of flour to reduce carbs by 5g per serving
• Serve with a side of non-starchy vegetables like roasted Brussels sprouts to balance the meal’s glycemic impact
• Keep portions to a ½-cup serving (about 18g net carbs) and pair with lean protein to slow glucose absorption

Pro Tips

• Slice potatoes directly into cold water to prevent browning, then pat completely dry before arranging
• For make-ahead convenience, assemble everything up to 24 hours in advance but don’t bake – just cover tightly and refrigerate
• If sauce seems to separate after baking, it’s likely because it boiled too vigorously – next time, lower the oven temperature to 350°F (175°C)
• For extra richness, replace ¼ cup of the milk with heavy cream
• A sprinkle of ¼ teaspoon nutmeg in the sauce adds a subtle warmth that complements the cheese perfectly