A comforting and delicious potato casserole with layers of creamy cheese and crispy bacon.
Preheat your oven to 350°F (175°C).
Preheating ensures even cooking from the start.
In a saucepan, melt the butter over medium heat. Stir in the flour and cook for 1 minute.
Cooking the flour removes its raw taste, enhancing the sauce.
Gradually whisk in the milk, cooking until the mixture thickens slightly.
Whisk constantly to avoid lumps in the sauce.
Stir in the cheddar and brie cheeses until melted and smooth. Season with salt and pepper.
Add the cheese gradually to ensure it melts evenly.
Butter a baking dish. Layer half of the potato slices, onions, and bacon. Pour half of the cheese sauce over the layers. Repeat with the remaining ingredients.
Ensure the layers are even for consistent cooking.
Bake the casserole in the preheated oven for 1 hour, or until the potatoes are tender and the top is golden brown.
Check the potatoes with a fork for doneness before removing from the oven.
Let the casserole cool for 10 minutes before serving.
Cooling allows the layers to set, making it easier to serve.