My grandmother’s scalloped potatoes always featured one unexpected ingredient that elevated the dish beyond the ordinary. This version carries on that tradition with a creamy twist.
The secret lies in layering thinly sliced potatoes with rich cream of mushroom soup, creating a dish that’s both comforting and deeply flavorful. Each bite delivers tender potatoes enveloped in a velvety sauce.
I’ve refined this method over years of testing, perfecting the balance between creamy texture and earthy mushroom depth. The result is a side dish that steals the show at any meal.
Ready in about an hour, this recipe transforms simple ingredients into something extraordinary. The layers bake together into a golden, bubbling masterpiece.
Ingredients for Scalloped Potatoes Recipe Cream of Mushroom
Thinly sliced potatoes, creamy mushroom sauce, and melty cheese create this layered indulgence.
| Ingredient | Amount | Notes |
|---|---|---|
| Russet Potatoes 🥔 | 2 lb | Thinly sliced, peeled or unpeeled |
| Cream of Mushroom Soup 🍲 | 2 cans | 10.5 oz cans, undiluted |
| Whole Milk 🥛 | 1 ½ cups | Full-fat for creaminess |
| Unsalted Butter 🧈 | 4 tbsp | Melted for roux |
| All-Purpose Flour 🌾 | 3 tbsp | For thickening sauce |
| Yellow Onion 🧅 | 1 whole | Finely diced for base |
| Fresh Cremini Mushrooms 🍄 | 8 oz | Sliced for earthy depth |
| Garlic Cloves 🧄 | 3 cloves | Minced for aroma |
| Sharp Cheddar Cheese 🧀 | 2 cups | Shredded from block |
| Parmesan Cheese 🧀 | ½ cup | Freshly grated for topping |
| Salt 🧂 | 1 ½ tsp | Diamond Crystal kosher |
| Black Pepper 🌶️ | ½ tsp | Freshly ground preferred |
| Dried Thyme 🌿 | ½ tsp | For herbal complexity |
| Paprika 🌶️ | ¼ tsp | Sweet or smoked variety |
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The potatoes are foundational—Russets offer the ideal starch content for creamy texture. Yukon Golds work too but require slightly less baking time. Cream of mushroom soup is non-negotiable; Campbell’s or Progresso are reliable brands. For the cheddar, Cabot or Tillamook provide superior melt and flavor. Always shred cheese from a block (pre-shredded contains anti-caking agents that affect texture).
Need a shortcut? Pre-sliced mushrooms save time without sacrificing quality. No fresh mushrooms? Dried porcini at one-third the amount adds intense umami. For a gluten-free version, cornstarch at 1 tbsp per tbsp flour works as thickener. Whole milk can be swapped for half-and-half (even richer) or 2% milk (lighter but less velvety).
Assemble and refrigerate up to 24 hours before baking. Leftovers keep 4-5 days refrigerated, reheating best in oven covered with foil. Freezes beautifully for 2-3 months—thaw overnight before reheating to preserve creamy texture.
Why You’ll Love This Recipe
- One Pot Magic: I just layer sliced Russets with cream of mushroom soup and milk, then let the oven do the work.
- Rich Comfort: The buttery sauce soaks into every potato slice, and that earthy mushroom flavor hits just right.
- Feeds the Gang: I’ve served this for Sunday dinner and potlucks alike—always disappears first.
- Stretches Far: Leftovers reheat beautifully, and the ingredients cost less than a takeout meal for four.
Step-by-Step Instructions for Scalloped Potatoes Cream of Mushroom
Master this method for perfectly layered, creamy potatoes with rich mushroom depth every time.
Step 1: Prepare the Creamy Mushroom Sauce Base
In a large saucepan over medium heat, melt the 4 tbsp Unsalted Butter until it begins to foam. Immediately whisk in the 3 tbsp All-Purpose Flour to create a smooth roux. Cook for 1-2 minutes, stirring constantly, until the mixture turns a light golden color and smells nutty.
Gradually pour in the 1.5 cups Whole Milk while whisking continuously to prevent lumps from forming. Add the 2 cans Cream of Mushroom Soup, 1.5 tsp Salt, 0.5 tsp Black Pepper, 0.5 tsp Dried Thyme, and 0.25 tsp Paprika. Reduce heat to medium-low and simmer for 5 minutes until the sauce thickens enough to coat the back of a spoon.
Step 2: Sauté the Aromatic Vegetable Foundation
In a separate skillet over medium heat, add the finely diced 1 whole Yellow Onion and sliced 8 oz Fresh Cremini Mushrooms. Cook for 6-8 minutes until the onions are translucent and the mushrooms release their moisture, then begin to brown slightly at the edges.
Add the minced 3 cloves Garlic Cloves and cook for an additional 1-2 minutes until fragrant, stirring frequently to prevent burning. The mixture should be soft and aromatic with a deep, earthy scent. Remove from heat and set aside to cool slightly before incorporating into the sauce.
Step 3: Layer and Assemble the Potato Casserole
Preheat your oven to 375°F. Thinly slice the 2 lb Russet Potatoes into ⅛-inch thick rounds, either peeled or unpeeled based on preference. Lightly grease a 9×13-inch baking dish with additional butter or nonstick spray.
Begin layering by spreading a thin coating of the mushroom sauce on the bottom of the dish. Add a single layer of potato slices, slightly overlapping. Sprinkle with ¼ of the 2 cups Sharp Cheddar Cheese. Repeat this pattern, adding the sautéed onion-mushroom mixture between layers, until all potatoes are used. Finish with a final layer of sauce and sprinkle the remaining Sharp Cheddar Cheese on top.
Step 4: Bake to Golden, Bubbling Perfection
Cover the dish tightly with aluminum foil and bake for 45 minutes. Then, carefully remove the foil and sprinkle the 0.5 cup Parmesan Cheese evenly over the top. Return to the oven, uncovered, and bake for an additional 25-30 minutes until the potatoes are tender when pierced with a knife and the top is golden brown with bubbling edges.
Let the casserole rest for 10 minutes before serving. This rest period allows the layers to set and the flavors to meld together. The sauce should be thick and creamy, coating each potato slice, with the cheese forming a beautifully browned crust on top.
Pro Tips For Making Scalloped Potatoes Recipe Cream Of Mushroom
- Slice Evenly: Cut russet potatoes into 1/8-inch thick slices—any thicker and they won’t cook through, any thinner and they’ll turn to mush. I learned this the hard way after pulling out a tray of half-raw, half-mushy potatoes.
- Thin the Soup: Mix the cream of mushroom soup with whole milk before layering—straight from the can it’s too thick and won’t seep between the potato layers. About 1 cup milk to 1 can soup does the trick.
- Skip the Boil: Resist the urge to parboil the potatoes first. They’ll absorb too much liquid and turn gluey in the oven—just layer them raw and let the heat do the work.
- Butter the Dish: Grease the baking dish with unsalted butter, not just flour, to prevent sticking and add richness. My grandmother swore by this, and she was right.
Essential Equipment for scalloped potatoes recipe cream of mushroom
Baking Dish Essentials
I always reach for my 9×13-inch glass baking dish—the clear sides let me monitor browning. Pyrex is my go-to brand for even heat distribution. For smaller batches, an 8×8-inch works perfectly with halved ingredients. 💡
Mandoline for Perfect Slices
A mandoline slicer is a game-changer for consistent ⅛-inch potato slices. I use the OXO Good Grips model with safety guard—it’s affordable and prevents uneven cuts that lead to some potatoes being undercooked.
No mandoline? Use a very sharp chef’s knife and cut carefully. The key is uniformity so everything cooks at the same rate.
Saucepan for Sauce
A 3-quart heavy-bottomed saucepan prevents scorching when making your roux and sauce. I swear by my All-Clad stainless steel pot—it conducts heat beautifully and cleans up easily. The heavy base prevents hot spots that can burn your sauce.
Whisk for Smoothness
Invest in a balloon whisk for lump-free sauce. My 10-inch silicone-coated whisk from RSVP International glides through the roux and milk mixture effortlessly. The silicone coating also protects nonstick surfaces if you’re using those.
Skillet for Sautéing
A 12-inch stainless steel skillet gives mushrooms and onions plenty of room to brown properly. I use my Cuisinart Chef’s Classic—it’s durable and heats evenly. Crowding the pan steams rather than browns, which affects flavor development.
Nutrition Facts
Frequently Asked Questions
Can I make this ahead of time?
Assemble the dish, cover tightly, and refrigerate for up to 24 hours before baking. Add 10-15 minutes to the baking time if cooking straight from the fridge.
What’s the best way to slice the potatoes evenly?
Use a mandoline slicer for perfect ⅛-inch slices. No mandoline? Use a sharp knife and cut carefully for uniform thickness. Uneven slices may cook at different rates.
Can I use a different type of cheese?
Yes! Swap cheddar for Gruyère or Monterey Jack for a milder flavor. Avoid pre-shredded cheese, as it contains anti-caking agents that affect texture.
Why did my sauce turn out thin?
This usually happens if the sauce wasn’t simmered long enough. Cook the roux and milk mixture for the full 5 minutes until it coats the back of a spoon. If needed, mix 1 tbsp cornstarch with cold water and stir in before baking.
Trained in classic French technique but raised on slow-cooked ribs and spicy rubs, she blends culinary skill with smoke and soul.
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