Homemade Scalloped potatoes with creamy alfredo sauce and mushrooms. This cheesy scalloped potatoes recipe is easy and loaded with lots of umami flavor and garlic! You will love these scalloped potatoes from scratch!

mushroom scalloped potatoes

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We love potatoes! Whether it’s potato soup, oven-roasted potatoes (wedges), mashed potatoes, or potato pancakes we have recipes for you! Potatoes go such a long way, use them in breakfast potatoes (hashbrowns), or cook them whole in the skins for the perfect baked potato! You can’t go wrong with this vegetable!

What are Scalloped Potatoes?

Scalloped potatoes (au gratin,) are a creamy potato dish baked in a cream sauce and then topped with grated cheese. The golden cheese crust locks the sauce into the thickly cut potatoes to make saucy potatoes and thicken the gravy. I arrange slices of boiled potatoes into a baking dish and top it with an easy mushroom alfredo sauce. You can bake and steam the potatoes in a square baking dish with a little water or use a microwave or the instant pot to make fork-tender potatoes. We find it best to cook a potato in minimal water to get the most nutrients out of the potatoes.

Best Potatoes For Scalloped:

The best potatoes to use for baking potatoes in a sauce are starchy Idaho potatoes or something like a russet potato. Russet potatoes are great for baking in sauces and the flaky texture goes best with creamy sauces and cheese. Potatoes should always be stored in dark places so they don’t turn green. Avoid buying green potatoes at the store, they have been exposed to the light. Typically, peeling the green potatoes can reduce the levels of glycoalkaloid, and if you can remove the green color below the surface of the peel then you can still eat the potatoes after cooking.

scalloped potatoes

Can You Make Scalloped Potatoes Ahead of Time?

This potato au gratin dish is a make-ahead recipe! That means you prep scalloped potatoes the night before! Because the potatoes are cooked before assembling all you would need to do is cool the potatoes first and then assemble them. You can easily continue to bake the casserole immediately after prep but since the potatoes are precooked they can keep long before baking. This recipe makes a good-sized batch so it’s best to reserve half of the sauce for another casserole and freeze it.

To make ahead: assemble cooked and cooled potatoes into a baking dish. Pour sauce over the top and cover well and refrigerate until needed. This can stay in the fridge for up to 5 days. The sauce can be hot or warm, it will thicken as it sits. 

To Freeze Scalloped Potatoes:

Cook and cool the potatoes before slicing. Arrange the precooked potatoes in a baking dish (or disposable pan.) Pour cooled alfredo sauce over the potatoes and double-wrap with foil. I like to wrap casseroles in a grocery bag to prevent frost. Keep frozen for up to 3 months. Thaw in the fridge before baking and follow the baking instructions in the recipe.

how to freeze scalloped potatoes

Note: it’s important to make scalloped potatoes with cream for the freezer. Using a milk sauce can curdle and have a grainy texture.

Ingredients Needed:


  • Potatoes: russet and Idaho potatoes are ideal for this casserole! If you’re using Yukon Gold or red potatoes you can leave the potato skins on since the waxy flesh helps them stay on.
  • Mushrooms: white button whole mushrooms is what I used. You can use Baby Bella mushrooms or Portobella mushrooms. Cut them into slices.
  • Cream Sauce: is made mainly from heavy cream, parmesan cheese, and butter. The mushroom soup mix can be replaced with an onion soup mix or any dry soup mix for extra flavor. Typically, soup mixes have some kind of thickener like starch.
  • Seasonings: simple salt and pepper will flavor this alfredo sauce plentiful, season to taste. However, adding fresh garlic and a mushroom soup mix will add lots of savory flavors!
  • Cheese: grated mozzarella cheese is used for the top to make a golden crust and the parmesan cheese in the sauce helps thicken the cream.

How To Make Scalloped Potatoes:

It is so easy to make this recipe for scalloped potatoes! A potato peeler is not necessary to prep the potatoes. Simply, place the potatoes into a pot with the skins on and boil potatoes until fork-tender. The potatoes are done boiling for around 15-20 minutes.  You could take the extra step and bake potatoes in the oven with 1/2 cup of water but that will take about 40 minutes.

  1. First cook the potatoes until tender.
  2. Prep and cut all the ingredients. Crush the garlic and set aside.
  3. Heat a frying pan with olive oil and butter. Saute the mushrooms and onion until soft and then add the garlic. Cook for 1 more minute.
  4. Add the seasonings and soup mix.
  5. Stir in the heavy cream and parmesan cheese and bring to a boil. Simmer for 5 minutes uncovered.
  6. Assemble thickly cut potatoes into a 9×13 pan, pour sauce over the potatoes, and sprinkle with mozzarella cheese.
  7. Bake covered at 400°F for 30 minutes. Then uncover and bake until the cheese crust gets browned. You know it’s done when the potato casserole is bubbling.

Baker’s Tip: this scallop potatoes recipe can make two 9×13 casseroles, one for the freezer and one to bake. Double the potato amount to make two casseroles.

Have you made this potato recipe? Leave a comment below on how much you like it and the ways you use this mushroom alfredo sauce! 

How To Make Scalloped Potatoes in a Crockpot: 

Simply prep and assemble a single portion of ingredients into a 7-quart slow cooker. Cook on high for 2-3 hours or low for 4-6 hours. Using a slow cooker is a great way to bring this along to a potluck or gathering, plug it in to keep it warm or cook over high to reheat and cook everything. 

What Goes With Scalloped Potatoes? 

Scalloped potatoes with cheese can be good to serve as a meal on its own or as a side! These easy scalloped potatoes are perfect for a Sunday dinner and tasty enough to serve on Holidays, with Christmas ham! Here are creative ways to eat this potato dish and ideas to serve up the sauce. 

  • Serve with a meat main course like Grilled steak, pork chops, or crispy chicken
  • Pair with a buttered slice of bread and fruit jam
  • We love Baked Salmon with potatoes! 
  • Mix in grated carrots or bacon pieces into the alfredo sauce. 
  • Leafy greens (salad) or steamed broccoli
  • Baked beans or frozen corn
  • Sauerkraut or some kind of cabbage salad
  • Reserve some of the Mushroom alfredo sauce to make with ravioli or other pasta. 


What is the Difference between Au Gratin and Scalloped Potatoes?

Generally, scalloped potatoes are a potato dish, baked with milk or a sauce. Whereas a gratin dish can be made with pasta, meat, and other vegetables.

Are Potatoes Gluten-free?

Yes, raw potatoes are gluten-free and contain no gluten.


BEST Scalloped Potato Tips:

  1. I cut my potatoes into thick slices for this potato dish, because the potatoes are pre-cooked it’s best to make them thicker so they don’t break apart. If starting with raw potatoes you would want to slice them thin using a mandoline. Thin slices may need to be layered between the sauce.
  2. Allow the potato casserole to sit for 10 minutes for the sauce to thicken.
  3. Use a shallow dish when baking so the sauce doesn’t bake over. I also use a shallow pan when sauteing the mushrooms and onions.
  4. Broil the cheese crust before serving. Baking cheesy potatoes in the open, for too long can dry out the cheese so, a broiler speeds it up without drying out the casserole.
  5. Use rich cream like heavy whipping cream so the casserole doesn’t curdle or get grainy in texture. This is also key for freezing scalloped potatoes.
  6. This is not a roux-based sauce so it will not look thick and creamy when simmering. However, the sauce will thicken with the potatoes in the oven when baking. This sauce is gluten-free if using a soup mix without added flour.
  7. If you prefer a thick and creamy sauce add more grated parmesan cheese to the cream and adjust the salt accordingly. 
  8. Cover the potatoes with foil when baking. This creates steam and doesn’t dry out the casserole.
  9. Don’t use small potatoes or baby ones, you want to make even slices.
  10. Use disposable pans when freezing so you don’t have to worry about the dish cracking. 
  11. Bake at a high temperature to simmer the sauce in the potatoes.  I will broil the casserole open, in the last 5 minutes of baking.
  12. Leftovers reheat well in the microwave or cover and bake until heated thoroughly. 

Scalloped Potato Recipe: 

Mushroom Scalloped Potatoes

Prep Time: 20 minutes
Cook Time: 40 minutes
Total Time: 1 hour
Servings: 12 servings
Homemade Scalloped potatoes with creamy alfredo sauce and mushrooms. This cheesy scalloped potatoes recipe is easy and loaded with lots of umami flavor and garlic! You will love these scalloped potatoes from scratch!


  • 1 9x13 baking dish
  • 1 shallow frying pan
  • 1 sheet of aluminum foil (to cover casserole)



  • 2 1/2 lbs Russet potatoes
  • 2 cups mozzarella cheese

Mushroom Alfredo Sauce:

  • 4 3/4 cups heavy cream
  • 4 oz unsalted butter (1 stick)
  • 2 Tbsp olive oil
  • 8 oz mushrooms (sliced)
  • 1 onion (diced)
  • 1 head garlic (crushed)
  • 2 tsp salt
  • 1/2 tsp black pepper
  • 1 cup parmesan cheese (grated)



  • boiled potatoes
    Boil the potatoes in 2 cups of water until fork-tender (about 15 minutes.) Remove and cool on a plate. Set aside.
  • sautéed mushrooms and onion
    In a large skillet over medium-high heat, melt the butter and olive oil. Saute the mushrooms and onion until soft (about 10 minutes.) Add the garlic and cook for 1 more minute.
  • Add the seasonings and soup mix.
  • mushroom alfredo sauce
    Stir in the heavy cream and parmesan cheese and bring to a boil. Simmer for 2 minutes, uncovered.
  • scalloped potatoes
    Peel the skins off the potatoes and slice them into 1/2-inch slices. Assemble into a 9x13 baking dish.
  • mushroom scalloped potatoes
    Pour 4-5 cups of the mushroom alfredo sauce over the potatoes and sprinkle with mozzarella cheese.
  • how to bake scalloped potatoes
    Bake covered at 400°F for 30 minutes. Then uncover and broil for 5 minutes to make a browned cheese crust.


**Mushroom Alfredo Sauce makes about 6.5 cups of sauce, this is enough for 2 casseroles, or reserve the other half for another alfredo dish. 
  • You can freeze this scalloped potato recipe after assembling it or make it ahead and store it in the fridge for up to 5 days. 

Nutrition per serving

Serving: 1servingCalories: 584kcalCarbohydrates: 23gProtein: 13gFat: 50gSaturated Fat: 31gPolyunsaturated Fat: 2gMonounsaturated Fat: 14gTrans Fat: 0.3gCholesterol: 147mgSodium: 671mgPotassium: 592mgFiber: 2gSugar: 4gVitamin A: 1814IUVitamin C: 8mgCalcium: 277mgIron: 1mg


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