Bring to Simmer: Increase the heat slightly to bring the mixture to a gentle simmer. Avoid a full boil to prevent the cream from curdling.
Cook: Cover the skillet, reduce the heat to medium-low, and let the mixture simmer gently. Cook until the potatoes are nearly tender when pierced with a knife, which will take about 15 to 20 minutes. Stir occasionally to ensure even cooking.
Adjust Seasoning: Taste the sauce and adjust the seasoning if needed, adding more salt and pepper to suit your taste.
Prepare the Casserole Dish
Grease the Dish: While the potatoes are simmering, butter an 8 x 8-inch baking dish or equivalent-sized dish. If you prefer individual servings, you can use five to six small casserole dishes.
Assemble the Dish
Transfer Mixture: Once the potatoes are nearly tender, transfer the mixture from the skillet to the prepared baking dish. Spread it evenly.
Top with Cheese: Sprinkle the mixed cheeses (Cheddar, Fontina or Provolone, and Parmesan) evenly over the top of the potatoes. This will create a delicious, cheesy crust.
Bake the Dish
Bake: Place the baking dish in the preheated oven and bake for 10 to 15 minutes, or until the sauce is bubbling and the cheese is melted and golden brown. The exact baking time may vary depending on the size and depth of your dish.
Cool Slightly: Allow the dish to cool for a few minutes before serving. This will help the cheese set slightly and make serving easier.
Garnish and Serve
