Creamy, cheesy, and dependable for family dinners or holiday meals, scalloped red potatoes layer thin potato slices with sweet onion and a smooth cheddar-Parmesan sauce. The potatoes bake until fork-tender while the seasoned sauce turns thick, bubbly, and rich around every layer.
This is a great side dish when you want something more substantial than basic roasted potatoes but still need a recipe that fits naturally beside chicken, beef, turkey, or other comforting mains. Red potatoes hold their shape nicely in the oven, giving you tender slices without the layers completely falling apart.
The cheese sauce is also made separately before baking, which helps it stay smooth and evenly seasoned. Sharp cheddar supplies most of the creamy cheese flavor, Parmesan adds a savory finish, and a simple blend of thyme, parsley, garlic, paprika, salt, and pepper keeps the potatoes flavorful without overwhelming them.
Because the casserole rests briefly after baking, the sauce has time to settle around the potatoes. That makes the finished dish easier to scoop and especially convenient when you are serving several people from a large 9 × 13-inch baking dish.
Ingredients
You only need familiar ingredients to build the creamy potato layers, but each one contributes something important to the finished casserole.
- Red potatoes: Use 1 1/2 pounds sliced into thin, approximately 1/8-inch rounds. Uniform slices are especially important because they help every layer become tender at roughly the same time.
- Sweet yellow onion: About 3/4 cup adds mild sweetness and savory flavor between the potato layers.
- Butter: Three tablespoons form the base of the roux and give the sauce extra richness.
- All-purpose flour: Three tablespoons thicken the milk into a sauce sturdy enough to coat the potatoes instead of pooling at the bottom of the pan.
- 2% milk: Two cups create the creamy base without making the dish excessively heavy.
- Sharp cheddar cheese: Use 1 1/4 cups for the primary cheese flavor and creamy texture. Extra-sharp cheddar also works when you prefer a stronger cheese taste.
- Parmesan cheese: Two-thirds cup of freshly grated Parmesan contributes saltiness and a deeper savory character.
- Garlic powder: Half a teaspoon seasons the sauce evenly without adding pieces of fresh garlic between the layers.
- Dried thyme: Half a teaspoon gives the creamy potatoes a subtle herb flavor.
- Dried parsley: One teaspoon adds another mild savory note to the cheese sauce.
- Paprika: A small 1/8 teaspoon adds gentle warmth and color.
- Salt and black pepper: Half a teaspoon of fine salt and 1/8 teaspoon freshly ground pepper balance the sauce.
Cooking Steps
STEP 1: Heat your oven to 400°F (200°C). Prepare a 9 × 13-inch baking dish with a light coating of butter or cooking spray. Slice the red potatoes into even 1/8-inch rounds and finely chop the sweet onion so everything is ready before you begin the cheese sauce.
STEP 2: Melt the butter in a medium saucepan over medium heat. Once it is gently bubbling, stir in the flour along with the parsley, garlic powder, thyme, paprika, salt, and black pepper. Cook for about one minute while stirring continuously. You want the flour cooked slightly without allowing the roux to become brown.
STEP 3: Lower the heat and slowly add the milk, stirring constantly as you pour. Adding it gradually makes it much easier to create a lump-free sauce. Once the milk is completely incorporated, bring the heat back to medium and let the mixture reach a gentle simmer.
STEP 4: Keep stirring as the sauce heats. It should begin to thicken after roughly a minute of gentle simmering. Remove the saucepan from the heat, then stir in the shredded cheddar and grated Parmesan. Continue mixing until the cheeses are completely melted and the sauce looks smooth and creamy.
STEP 5: Arrange roughly half of the red potato slices across the prepared baking dish. Slight overlap between the slices is fine. Scatter the chopped sweet onion evenly over this first potato layer, then spoon about half of the warm cheese sauce across the top.
STEP 6: Add the remaining potato slices, spreading them as evenly as possible. Pour over the rest of the cheese sauce, making sure the exposed potato surfaces are coated. Good sauce coverage helps the thin potato slices stay moist while they bake.
STEP 7: Bake for approximately 45 to 55 minutes. The casserole is ready when the cheese sauce is bubbling around the edges and a fork slides easily through the potato slices. For a more deeply browned surface, place the dish under the broiler for about two minutes, watching closely.
STEP 8: Remove the baking dish from the oven and leave it undisturbed for about 10 minutes. This short resting period gives the thickened cheese sauce time to settle and makes the layered potatoes much easier to serve cleanly.
Serving Ideas for Scalloped Red Potatoes
These creamy potatoes work particularly well with simple roasted or baked proteins because the cheese sauce already brings plenty of richness to the plate.
Roast chicken is an excellent choice because its savory juices complement the cheddar and Parmesan without competing with them. The potatoes are also a natural addition to roast beef or pork tenderloin when you want a comforting dinner with classic flavors.
For holiday meals, serve them alongside roasted turkey and a green vegetable such as green beans, broccoli, or Brussels sprouts. A fresh vegetable side is particularly useful because it balances the creamy texture of the potatoes.
Can I leave the skins on red potatoes?
Yes. Red potato skins are relatively thin, so peeling is not necessary for this dish. Leaving them on also makes preparation faster and gives the finished casserole a slightly more rustic appearance. Just wash and scrub the potatoes thoroughly before slicing.
Why should the potatoes be sliced so thinly?
Thin, uniform slices are important because the potatoes cook directly in the casserole rather than being boiled beforehand. Keeping them near 1/8 inch thick helps them become tender within the 45 to 55 minute baking time while also creating neat, creamy layers.
A mandoline makes consistent slices particularly easy, although a sharp chef’s knife works as well when used carefully.
Helpful Tips
- Grate the cheese yourself when possible. Freshly grated cheddar and Parmesan usually melt into the milk sauce more smoothly than cheeses containing anti-caking coatings.
- Keep stirring the roux. Continuous movement prevents the flour and butter mixture from browning and helps create a pale, creamy finished sauce.
- Check the center for tenderness. Potatoes near the edges may soften first, so test a slice near the middle of the casserole before removing it from the oven.
Can I prepare the potatoes ahead of time?
You can assemble the casserole somewhat in advance and keep it refrigerated until you are ready to bake it. Because a chilled baking dish and cold potatoes may need longer in the oven, use potato tenderness rather than relying only on the original baking time.
If possible, assembling it shortly before baking gives you the most predictable results.
How do I know when scalloped potatoes are done?
The bubbling sauce is one useful visual clue, but potato tenderness matters more. Insert a fork or thin knife into the center of the casserole. It should pass through the potato layers easily without noticeable resistance.
If the potatoes still feel firm, continue baking and check again after several minutes.
How to Store & Reheat
Allow leftover potatoes to cool before transferring them to a covered container, or tightly cover the baking dish if you are keeping the leftovers in the same pan. Refrigerate them promptly and use them within about three to four days.
For individual portions, microwave the potatoes until hot throughout. Adding a small splash of milk before reheating can help loosen sauce that has thickened considerably in the refrigerator.
Larger portions can be reheated in a covered baking dish in a moderate oven until warmed through. Covering the dish during most of reheating helps prevent the exposed potatoes and cheese sauce from drying out.
Freezing is possible, but cream and cheese sauces can change texture after thawing, becoming slightly grainy or separated. For the smoothest consistency, these potatoes are better refrigerated and reheated rather than frozen.
Can I use extra-sharp cheddar instead?
Absolutely. Sharp and extra-sharp cheddar both work with the Parmesan sauce. Extra-sharp cheddar creates a more pronounced cheese flavor, which can be especially good when the potatoes are served with a simply seasoned main course.
Whichever cheddar you choose, grate it before making the sauce so it melts quickly after the saucepan is removed from the heat.
The combination of tender red potatoes, mild sweet onion, cheddar, and Parmesan makes this casserole a versatile side for everything from an ordinary family dinner to a holiday spread. Keeping the potato slices thin, building a smooth roux-based sauce, and allowing the baked casserole to rest are the small details that make the creamy layers come together reliably.
Scalloped Red Potatoes
Ingredients
- 2 cups 2% milk
- 1/2 teaspoon dried thyme
- 2/3 cup Parmesan cheese freshly grated
- 1 1/2 pounds red potatoes cut into 1/8-inch-thick slices
- 1/8 teaspoon freshly ground black pepper
- 3 tablespoons unsalted butter
- 1 1/4 cups sharp or extra-sharp cheddar cheese shredded
- 3/4 cup sweet yellow onion chopped
- 1 teaspoon dried parsley
- 1/2 teaspoon fine salt
- 3 tablespoons all-purpose flour
- 1/8 teaspoon ground paprika
- 1/2 teaspoon garlic powder
Instructions
- Preheat the oven to 400°F (200°C). If necessary, slice the red potatoes into uniform 1/8-inch-thick rounds and finely chop the sweet yellow onion. Shred the cheddar and Parmesan cheeses if they have not already been prepared.
- Place a medium saucepan over medium heat and melt the butter until it begins to bubble gently.
- Add the flour, dried parsley, garlic powder, dried thyme, salt, paprika, and black pepper to the melted butter. Stir continuously until thoroughly combined, then cook the mixture for approximately 1 minute, keeping it moving so the roux bubbles without browning.
- Reduce the heat to low. Gradually pour the milk into the roux while stirring constantly to maintain a smooth consistency and prevent lumps from forming.
- After all the milk has been incorporated, return the heat to medium and bring the mixture to a gentle simmer. Continue stirring until the sauce thickens, approximately 1 minute.
- Remove the saucepan from the heat. Add the shredded cheddar and grated Parmesan, stirring until both cheeses have melted completely and the sauce is thick, smooth, and evenly blended.
- Lightly coat a 9 × 13-inch baking dish with butter or cooking spray.
- Spread half of the sliced red potatoes across the bottom of the prepared dish in an even layer. Distribute all of the chopped onion over the potatoes.
- Pour approximately half of the cheese sauce over the potato-and-onion layer, spreading it evenly so the vegetables are well coated.
- Arrange the remaining potato slices over the first layer. Pour the rest of the cheese sauce across the top, ensuring the potatoes are thoroughly covered.
- Bake in the preheated oven for 45–55 minutes, or until the sauce is bubbling and the potato slices are tender when pierced with a fork.
- For a more deeply browned, bubbling surface, broil the dish for an additional 2 minutes at the end of baking, watching it closely to prevent scorching.
- Allow the scalloped potatoes to rest for approximately 10 minutes before serving so the sauce can settle slightly and the layers are easier to portion.
Notes
- Freshly grated cheddar and Parmesan melt more smoothly into the sauce than many pre-shredded varieties.
- Keep the roux moving continuously while it cooks to prevent it from browning.
- Make certain the potato slices are thoroughly coated with cheese sauce before baking so they remain moist as they cook.