A rich and creamy scalloped potato dish, perfect for family dinners or special occasions.
Preheat your oven to 375°F and grease a baking dish.
Greasing the dish prevents sticking and makes cleaning easier.
Peel and thinly slice the potatoes and onion.
Use a mandoline slicer for uniform slices.
In a saucepan, melt the butter over medium heat. Stir in the flour, salt, and pepper until smooth.
Stir constantly to prevent lumps.
Gradually whisk in the milk and cook until the sauce thickens.
Keep stirring to avoid burning the sauce.
Layer half of the potatoes and onions in the baking dish. Pour half of the sauce over the layer. Repeat with the remaining potatoes, onions, and sauce.
Ensure even coverage of the sauce for consistent flavor.
Sprinkle the cheddar and parmesan cheese over the top.
Distribute the cheese evenly for a golden crust.
Bake in the preheated oven for 50 minutes or until the potatoes are tender and the top is golden brown.
Check doneness by inserting a knife into the potatoes; it should slide in easily.
Let the dish cool slightly before serving. Enjoy your creamy cheesy scalloped potatoes!
Allowing the dish to rest helps the layers set for easier serving.