Irresistible Scalloped Potatoes Au Gratin

Here is my favorite scalloped potatoes au gratin recipe, with a creamy cheese sauce made from scratch with butter, flour, milk, and two types of cheese, layered with thin slices of potatoes and baked until bubbly.

These scalloped potatoes are always a hit at family dinners and holiday gatherings. I love making them because they’re impressive enough for company but easy enough for a weeknight meal. Plus, who can resist all that melted cheese?

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What Kind of Potatoes Should I Use?

For scalloped potatoes, you’ll want to reach for starchy potatoes like Russets or Yukon Golds. Russets are the classic choice because they absorb the creamy sauce beautifully and create those tender, melt-in-your-mouth layers we all love. Yukon Golds are another great option since they hold their shape a bit better while still soaking up all that cheesy goodness. Avoid waxy potatoes like red potatoes or fingerlings for this recipe – they won’t break down enough and can end up feeling a bit too firm. When you’re prepping them, try to slice your potatoes as evenly as possible (about 1/8 inch thick) so they cook at the same rate and you don’t end up with some pieces that are mushy while others are still crunchy.

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Options for Substitutions

This recipe is pretty forgiving when it comes to swaps, so here are some options that work well:

• Potatoes: Russet potatoes are the classic choice here because they hold their shape and absorb the sauce nicely. You can use Yukon golds for a creamier texture, but I’d avoid waxy red potatoes as they don’t absorb the sauce as well.
• Milk and cream: If you don’t have cream on hand, you can use all milk (2 1/2 cups total) – the dish will be a bit less rich but still tasty. Or go the other way and use half-and-half for the whole amount if you want it extra creamy.
• Cheddar cheese: Sharp cheddar gives the best flavor, but you can swap in Gruyere, fontina, or even Monterey Jack. Each will give you a slightly different taste but all melt beautifully.
• Parmesan: Pecorino Romano makes a good substitute if that’s what you have in your fridge. It’s a bit saltier, so you might want to cut back slightly on the added salt.
• Butter and flour: These two create the roux that thickens your sauce, so they’re pretty essential to the recipe. Don’t skip them or your sauce will be too thin.

Watch Out for These Mistakes While Baking

The biggest mistake you can make with scalloped potatoes is slicing your potatoes unevenly or too thick, which leads to some pieces being mushy while others stay crunchy – aim for slices about 1/8 inch thick using a mandoline or sharp knife for consistent results.

Another common error is not cooking your roux (the butter and flour mixture) long enough, which can leave a raw flour taste in your sauce, so make sure to cook it for the full 1-2 minutes until it smells slightly nutty.

Skipping the resting time after baking is tempting, but those 5 minutes allow the sauce to thicken up and make serving much cleaner, and if you want extra crispy edges, try baking uncovered for the last 30 minutes instead of just 20.

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What to Serve With Scalloped Potatoes?

Scalloped potatoes are rich and cheesy, so they pair perfectly with simple roasted or grilled proteins like chicken, pork chops, or a nice steak. I love serving them alongside a basic green salad with a light vinaigrette to cut through all that creamy goodness. They also make a great side dish for holiday meals with ham or roast beef, and you really don’t need much else on the plate since they’re so filling. If you want to add another veggie, roasted green beans or steamed broccoli work well without competing with the potatoes.

Storage Instructions

Store: Leftover scalloped potatoes keep really well in the fridge. Just cover the dish tightly with foil or transfer to an airtight container, and they’ll stay good for up to 4 days. The flavors actually get even better the next day after everything has had time to meld together.

Freeze: You can freeze scalloped potatoes for up to 2 months, though the texture might be slightly different when thawed. Let them cool completely first, then wrap the dish tightly in plastic wrap and foil, or portion into freezer-safe containers. I find they work best when frozen before baking, but already-baked portions freeze okay too.

Reheat: To warm up your scalloped potatoes, cover with foil and bake at 350°F for about 20-25 minutes until heated through. You can also microwave individual portions for 2-3 minutes, stirring halfway. If they seem a bit dry, add a splash of milk or cream before reheating to bring back that creamy texture.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 2000-2200
• Protein: 60-70 g
• Fat: 110-125 g
• Carbohydrates: 180-200 g

Ingredients

For the cheese sauce:

• 4 tbsp butter (I like Kerrygold unsalted butter for this)
• 4 tbsp flour
• 1/2 cup onion
• 3 garlic cloves (freshly minced for best flavor)
• 2 cups milk (room temperature, about 70°F)
• 1/2 cup cream
• 2 tsp salt
• 1/4 tsp pepper
• 1/4 teaspoon ground nutmeg
• 1 1/2 cups cheddar (I use Tillamook sharp cheddar for best melting)
• 1/3 cup parmesan

For the assembly:

• 2.25 lb potatoes (peeled and sliced into 1/8-inch rounds)
• parsley

Step 1: Prepare Mise en Place and Preheat Oven

• 2.25 lb potatoes, peeled and sliced into 1/8-inch rounds
• 1/2 cup onion, diced
• 3 garlic cloves, freshly minced

Preheat your oven to 350°F.

While it heats, peel the potatoes and slice them into 1/8-inch rounds—I use a mandoline for consistent thickness, which ensures even cooking.

Dice the onion into small pieces, mince the garlic cloves fresh, and measure out all your remaining ingredients.

Having everything prepped and ready will make the sauce-building process smooth and prevent any burning or overcooking while you’re multitasking.

Step 2: Build the Cheese Sauce Base

• 4 tbsp butter
• 1/2 cup onion, diced
• 3 garlic cloves, freshly minced
• 4 tbsp flour

In a large pot or heavy-bottomed saucepan, melt the butter over medium heat.

Once melted and foaming, add the diced onion and cook for 5-6 minutes, stirring occasionally, until softened and translucent.

Add the minced garlic and cook for another minute until fragrant.

Sprinkle the flour over the mixture and stir constantly for 1-2 minutes to cook out the raw flour taste—this creates a roux that will thicken your sauce.

Step 3: Create the Cream Sauce and Season

• 2 cups milk, room temperature
• 1/2 cup cream
• 2 tsp salt
• 1/4 tsp pepper
• 1/4 teaspoon ground nutmeg
• 1 1/2 cups cheddar
• 1/3 cup parmesan

Gradually add the room-temperature milk and cream to the roux, stirring constantly to prevent lumps from forming.

Bring the mixture to a gentle boil, then immediately reduce the heat to low and simmer, stirring frequently, until the sauce thickens enough to coat the back of a spoon—this usually takes 5-8 minutes.

Once thickened, remove from heat and stir in the salt, pepper, and nutmeg.

Then add the cheddar and parmesan cheeses, stirring until completely melted and smooth.

I find that removing from heat before adding cheese prevents it from becoming grainy or separating.

Step 4: Combine Potatoes with Sauce and Assemble

• sliced potatoes from Step 1
• cheese sauce from Step 3
• 1/3 cup parmesan for topping

In a large bowl, add the sliced potatoes and pour the warm cheese sauce over them.

Gently fold together using a spatula or wooden spoon, being careful not to break the potato slices—you want them to stay intact for the best texture.

Pour the entire mixture into a 9×13-inch baking dish (or similar size), spreading it in an even layer.

Top with an additional sprinkle of parmesan cheese for extra flavor and a golden crust, then cover tightly with aluminum foil.

Step 5: Bake Covered and Then Finish with Browning

Bake the covered dish for 1 hour at 350°F.

The foil traps steam and helps the potatoes cook through gently without the top browning too quickly.

After 1 hour, carefully remove the foil and bake for an additional 20 minutes until the top is golden brown and bubbling at the edges.

This two-stage baking method ensures the potatoes are creamy and tender while the top gets crispy and delicious.

Step 6: Rest and Serve

• parsley, for garnish

Remove the gratin from the oven and let it rest for 5 minutes before serving.

This resting period allows the sauce to set slightly so it won’t run all over the plate.

Garnish with fresh parsley just before serving for a pop of color and freshness.

Irresistible Scalloped Potatoes Au Gratin

Delicious Irresistible Scalloped Potatoes Au Gratin recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 40 minutes mins

Cook Time 1 hour hr 15 minutes mins

Total Time 1 hour hr 55 minutes mins

Servings 8 servings

Calories 2100 kcal

Ingredients

  

For the cheese sauce::

• 4 tbsp butter (I like Kerrygold unsalted butter for this)
• 4 tbsp flour
• 1/2 cup onion
• 3 garlic cloves (freshly minced for best flavor)
• 2 cups milk (room temperature, about 70°F)
• 1/2 cup cream
• 2 tsp salt
• 1/4 tsp pepper
• 1/4 teaspoon ground nutmeg
• 1 1/2 cups cheddar (I use Tillamook sharp cheddar for best melting)
• 1/3 cup parmesan

For the assembly::

• 2.25 lb potatoes (peeled and sliced into 1/8-inch rounds)
• parsley

Instructions

 

• Preheat your oven to 350°F. While it heats, peel the potatoes and slice them into 1/8-inch rounds—I use a mandoline for consistent thickness, which ensures even cooking. Dice the onion into small pieces, mince the garlic cloves fresh, and measure out all your remaining ingredients. Having everything prepped and ready will make the sauce-building process smooth and prevent any burning or overcooking while you're multitasking.
• In a large pot or heavy-bottomed saucepan, melt the butter over medium heat. Once melted and foaming, add the diced onion and cook for 5-6 minutes, stirring occasionally, until softened and translucent. Add the minced garlic and cook for another minute until fragrant. Sprinkle the flour over the mixture and stir constantly for 1-2 minutes to cook out the raw flour taste—this creates a roux that will thicken your sauce.
• Gradually add the room-temperature milk and cream to the roux, stirring constantly to prevent lumps from forming. Bring the mixture to a gentle boil, then immediately reduce the heat to low and simmer, stirring frequently, until the sauce thickens enough to coat the back of a spoon—this usually takes 5-8 minutes. Once thickened, remove from heat and stir in the salt, pepper, and nutmeg. Then add the cheddar and parmesan cheeses, stirring until completely melted and smooth. I find that removing from heat before adding cheese prevents it from becoming grainy or separating.
• In a large bowl, add the sliced potatoes and pour the warm cheese sauce over them. Gently fold together using a spatula or wooden spoon, being careful not to break the potato slices—you want them to stay intact for the best texture. Pour the entire mixture into a 9x13-inch baking dish (or similar size), spreading it in an even layer. Top with an additional sprinkle of parmesan cheese for extra flavor and a golden crust, then cover tightly with aluminum foil.
• Bake the covered dish for 1 hour at 350°F. The foil traps steam and helps the potatoes cook through gently without the top browning too quickly. After 1 hour, carefully remove the foil and bake for an additional 20 minutes until the top is golden brown and bubbling at the edges. This two-stage baking method ensures the potatoes are creamy and tender while the top gets crispy and delicious.
• Remove the gratin from the oven and let it rest for 5 minutes before serving. This resting period allows the sauce to set slightly so it won't run all over the plate. Garnish with fresh parsley just before serving for a pop of color and freshness.