# What You’ll Need:
→ Vegetables
01 - 2 lbs Yukon Gold or Russet potatoes, peeled and thinly sliced
02 - 1 medium yellow onion, thinly sliced
→ Dairy
03 - 2 cups shredded sharp cheddar cheese
04 - 1 cup shredded mozzarella cheese
05 - 2 cups whole milk
06 - 2 tablespoons unsalted butter
07 - 2 tablespoons all-purpose flour
→ Seasonings
08 - 1 teaspoon salt
09 - 1/2 teaspoon black pepper
10 - 1/2 teaspoon garlic powder
11 - 1/4 teaspoon paprika
# How to Make It:
01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish thoroughly.
02 - Melt unsalted butter in a medium saucepan over medium heat. Add all-purpose flour and whisk continuously for 1 minute to form a roux.
03 - Gradually pour in whole milk, whisking constantly until smooth. Continue cooking and stirring for 3–4 minutes until slightly thickened.
04 - Remove pan from heat. Stir in salt, black pepper, garlic powder, and half the shredded cheddar and mozzarella cheeses until fully melted and smooth.
05 - Arrange half of the potato slices evenly in the prepared dish. Top with half the onion slices and half the cheese sauce. Repeat with remaining potatoes, onions, and sauce.
06 - Sprinkle the remaining shredded cheeses and paprika evenly over the top layer.
07 - Cover dish tightly with aluminum foil and bake for 40 minutes.
08 - Remove foil and bake for an additional 25–30 minutes, until potatoes are tender and the surface is golden brown.
09 - Allow to rest for 10 minutes before slicing and serving.
