This is the ultimate side dish for any occasion. Thinly sliced russet potatoes and onions are baked in a rich, homemade cheddar cheese sauce until impossibly tender and bubbling. The top crisps to golden perfection under the broiler for the perfect textural contrast.
Table of Contents
Why You Will Love This Recipe
You will love this recipe because it masterfully combines the comforting creaminess of classic scalloped potatoes with the indulgent, gooey cheese of potatoes au gratin. The from-scratch cheese sauce is simple to make and far superior to any canned soup shortcut, delivering deep, savory flavor. It’s a versatile dish that can be prepped ahead, pairs with everything from holiday ham to weeknight roast chicken, and is guaranteed to be the star of the dinner table.
Ingredients
- 4 russet potatoes (about 2 lbs), peeled and sliced into ¼-inch slices: Russets are ideal for their starch content, which helps thicken the sauce. A mandoline ensures even slices for consistent cooking.
- 1 yellow onion, sliced into rings: Adds a sweet, aromatic layer that balances the richness of the cheese.
- 3 tablespoons unsalted butter: The base for our roux. Using unsalted allows you to control the final salt level.
- 3 tablespoons all-purpose flour: Combined with butter to create a roux, which thickens the cheese sauce.
- ½ teaspoon kosher salt: Seasons the sauce base. You’ll add more to taste at the end.
- 2 cups whole milk, room temperature: Whole milk is essential for a rich, creamy sauce. Letting it come to room temperature helps prevent the sauce from seizing.
- 1 ½ cups mild cheddar cheese, shredded: Mild cheddar melts beautifully and provides classic flavor. For a sharper taste, use medium or sharp cheddar. Pre-shredded cheese contains anti-caking agents that can make sauces grainy; shredding your own is highly recommended.
- Salt and pepper to taste: Crucial for finishing and balancing the flavors.
Step-by-Step Instructions
- Prep & Layer: Preheat your oven to 400°F (200°C). Lightly grease an 8×8-inch or 2-quart baking dish. Arrange the sliced potatoes and onions in the prepared dish, staggering them in layers (potato, onion, potato, etc.).
- Make the Roux: In a medium saucepan over medium heat, melt the butter. Whisk in the flour and ½ teaspoon salt. Cook, stirring constantly with the whisk, for about 1 minute to cook out the raw flour taste.
- Create the Base Sauce: Slowly pour in the room-temperature milk while whisking continuously to avoid lumps. Cook, stirring often, until the mixture thickens and can coat the back of a spoon, about 5-7 minutes.
- Make it Cheesy: Reduce heat to low. Add all the shredded cheddar cheese at once and stir until the cheese is completely melted and the sauce is smooth, about 30-60 seconds. Remove from heat.
- Assemble: Pour the warm cheese sauce evenly over the layered potatoes and onions in the baking dish, ensuring it seeps into the layers. Cover the dish tightly with aluminum foil.
- Bake: Place the covered dish in the preheated oven and bake for 85-90 minutes. The potatoes should be completely tender when pierced with a knife.
- Crisp the Top (Optional): For a golden, crisp topping, remove the foil and switch the oven to broil. Broil for 2-4 minutes, watching closely, until the top is beautifully browned.
- Serve: Let the dish rest for 5-10 minutes before serving. Season with additional salt and black pepper to taste.
Expert Tips / Pro Tips
- Mandoline Magic: For perfectly even slices (which cook at the same rate), use a mandoline slicer. Always use the hand guard for safety.
- Sauce Consistency: The sauce will seem thin when you pour it over the potatoes, but it will thicken significantly as the potatoes release their starch during baking.
- Resting is Key: Allowing the dish to rest for a few minutes after baking lets the sauce set slightly, making it easier to serve neat portions.
- Cheese Choice: While mild cheddar is classic, feel free to experiment with Gruyère, Gouda, or a blend for a more complex flavor profile.
Variations & Substitutions
- Cheesy Scalloped Potatoes and Ham: Transform this into a main course by adding 1-2 cups of diced cooked ham between the layers of potatoes and onions.
- Garlic Herb: Add 2 minced garlic cloves to the butter when making the roux and stir 1 tablespoon of fresh thyme or rosemary into the cheese sauce.
- Potato Type: Yukon Gold potatoes can be used for a slightly richer flavor and creamier texture. No need to peel them.
- Gluten-Free: Substitute the all-purpose flour with an equal amount of a 1:1 gluten-free flour blend.
Serving Suggestions
This rich, cheesy dish is the quintessential holiday side, perfect alongside Herb Butter Roasted Turkey, Spiral Ham, or Prime Rib. For a comforting weeknight meal, pair it with Roasted Chicken or Pork Chops. Balance the richness with simple green vegetables like Roasted Carrots, Garlic Green Beans, or a crisp green salad.
Storage, Freezing & Reheating
- Storage: Cool completely, then cover tightly or transfer to an airtight container. Refrigerate for up to 4 days.
- Freezing: Assemble and bake the dish, then cool completely. Wrap tightly in plastic wrap and foil, or place in a freezer-safe container. Freeze for up to 2 months. Thaw overnight in the refrigerator before reheating.
- Reheating: Reheat individual portions in the microwave until hot throughout. For larger portions, reheat covered with foil in a 350°F (175°C) oven for 20-30 minutes, or until warmed through. Add a splash of milk if the sauce seems dry.
Nutrition Information
Per Serving (1 of 8 servings):
- Calories: 346 kcal
- Carbohydrates: 39g
- Protein: 13g
- Fat: 16g
- Saturated Fat: 10g
- Cholesterol: 48mg
- Sodium: 320mg
- Fiber: 3g
- Sugar: 6g
Cheesy Scalloped Potatoes
Ingredients
Equipment
Method
- Preheat oven to 400°F. Grease an 8×8-inch baking dish. Arrange sliced potatoes and onions in the dish, staggering them in layers.4 russet potatoes, 1 yellow onion
- In a saucepan over medium heat, melt butter. Whisk in flour and ½ tsp salt. Cook, stirring, for 1 minute.3 tablespoons unsalted butter, 3 tablespoons all-purpose flour, 1/2 teaspoon kosher salt
- Gradually whisk in milk until smooth. Cook, stirring often, until thickened, about 5-7 minutes.2 cups whole milk
- Reduce heat to low. Add shredded cheese and stir until completely melted and sauce is smooth. Remove from heat.1 1/2 cups mild cheddar cheese
- Pour cheese sauce evenly over the potatoes and onions. Cover dish tightly with aluminum foil.
- Bake for 85-90 minutes, until potatoes are tender when pierced with a knife.
- For a crisp top, remove foil and broil for 2-4 minutes until golden brown. Let rest 5-10 minutes, season with salt and pepper, and serve.1/2 teaspoon kosher salt, black pepper
Notes
FAQ
Can I make these ahead of time?
Yes! Assemble the dish completely (through step 5), cover tightly, and refrigerate for up to 24 hours before baking. You may need to add 5-10 minutes to the baking time if starting from cold.
What’s the difference between scalloped potatoes and au gratin?
Traditionally, scalloped potatoes are baked in a cream sauce without cheese, while au gratin potatoes include cheese. This recipe is a delicious hybrid, often called “cheesy scalloped potatoes.”
Why are my potatoes still hard?
The potatoes were likely sliced too thickly, or the oven temperature was too high, causing the sauce to thicken before the potatoes fully softened. Ensure slices are ¼-inch or thinner and bake at the recommended temperature.
Can I use pre-shredded cheese?
You can, but the sauce may not be as smooth. Pre-shredded cheese is coated with cellulose to prevent clumping, which can inhibit melting. Block cheese shredded by hand melts more smoothly.