Wash and peel the potatoes. Slice them into thin, even rounds. Thin slices cook evenly and create beautiful layers. Keep the slices similar in size for the best texture after baking.
Make the Cream Sauce
Melt the butter in a saucepan over medium heat. Add flour and whisk until smooth. Slowly pour in the milk and cream while whisking. Stir until the sauce becomes thick and creamy without lumps.
Add the Seasonings
Mix garlic, onion powder, salt, and black pepper into the sauce. Stir well until everything blends together. Cook for another two minutes so the flavors combine and become rich and delicious.
Add the Cheese
Remove the saucepan from the heat. Stir in both shredded cheeses. Mix until the cheese melts completely. The sauce should become smooth, creamy, and full of cheesy flavor.
Layer Everything
Grease the baking dish lightly. Arrange one layer of potatoes. Spoon some cheese sauce over the potatoes. Repeat the layers until all potatoes and sauce are used evenly.
Bake the Dish
Cover the baking dish with foil. Bake at 375°F for 60 minutes. Remove the foil and bake another 15 minutes until the top turns golden and the potatoes become perfectly tender.
Rest and Serve
Remove the dish from the oven. Let it rest for 10 minutes before serving. Sprinkle chopped parsley on top. This short resting time helps the creamy sauce set beautifully.
Notes
Slice potatoes evenly for perfect cooking.
Use freshly shredded cheese for smoother melting.
Add cooked bacon for extra flavor.
Mix mozzarella with cheddar for more stretch.
Add fresh thyme or rosemary.
Sprinkle Parmesan on top before baking.
Use half-and-half instead of heavy cream if preferred.