This recipe takes the classic scalloped potatoes and elevates it with a creamy and cheesy twist, perfect for any occasion.
Preheat your oven to 375°F (190°C).
Preheating ensures even cooking from the start.
Peel and thinly slice the potatoes and onions.
Using a mandoline slicer helps achieve uniform slices.
In a saucepan, melt the butter over medium heat, then whisk in the flour to create a roux.
Stir constantly to avoid lumps in the roux.
Gradually add the milk to the roux, whisking continuously until the sauce thickens.
Warm milk integrates more smoothly into the roux.
Layer the potato slices and onions in a buttered casserole dish, seasoning each layer with salt and pepper.
Overlap the potato slices slightly for a cohesive texture.
Pour the sauce over the layered potatoes and onions, ensuring even coverage.
Tap the dish gently to settle the sauce into the layers.
Sprinkle the grated cheese evenly over the top.
Use freshly grated cheese for the best melting quality.
Bake in the preheated oven for 45-50 minutes, or until the top is golden and bubbly.
Check doneness by inserting a knife into the center; it should slide through easily.
Let the gratin rest for 10 minutes before serving to allow the layers to set.
Resting enhances the dish's structure and flavor.
