2 ½cupsshredded cheeseyour favorite (see tips for my favorite)
Preheat the oven to 375°F.
Peel the potatoes and use a mandolin to cut the potatoes to ⅛" slices. Set aside.
In a small saucepan, heat the mushroom soup, milk, and sour cream together. Once it begins to simmer turn off the heat and stir in 1 cup of the shredded cheese and paprika.
Melt the butter in the bottom of a 12" skillet with high sides. Use a paper towel to rub the butter around the bottom and sides of pan until coated.
Working in a spiral pattern, slightly overlap the sliced potatoes until the bottom of the pan is covered. Spoon and spread out ¼ of the mushroom soup mixture. Sprinkle on one tablespoon of the fresh thyme. Repeat two more times.
Put the final layer of potatoes on the top and pour the last of the soup mixture on top. Cover with the last of the shredded cheese and thyme. Cover tightly with aluminum foil and bake for one hour.
Remove the foil and cook for another 10-15 minutes or until the top is golden brown and crusty. Remove from the oven and let rest at least 10 minutes before slicing and serving.
Mixing the cheese into the cream of mushroom soup sauce mixture prevents the cheese from becoming grainy while cooking.
If using dried thyme, use 4 teaspoons total.
Traditionally, scalloped potatoes use a cheese blend like gruyere and parmesan. I also love to mix in mozzarella and fontina. (This blend is often referred to as “pizza cheese mix” or “four cheese blend”.) You can use whatever cheese you prefer, even cheddar cheese is delicious.
Don’t skip the time for the time for the skillet scalloped potatoes to set up. This is what helps the layers grab ahold of each other like lasagna. It won’t be quite that firm, but it won’t immediately fall apart as you pick up a slice.
You can speed up the process of browning the top by placing the pan in the middle of the oven under the broiler. Cook for 3-5 minutes.