# What You 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 - ½ teaspoon black pepper
10 - ½ teaspoon garlic powder
11 - ¼ teaspoon paprika
# Steps:
01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish with butter or cooking spray.
02 - Melt butter in a medium saucepan over medium heat. Add flour and whisk continuously for 1 minute to form a roux.
03 - Slowly pour milk into the roux while whisking constantly to prevent lumps. Continue cooking until sauce thickens slightly, approximately 3 to 4 minutes.
04 - Remove saucepan from heat. Stir in salt, pepper, garlic powder, and half of the cheddar and mozzarella cheeses until fully melted and smooth.
05 - Arrange half the potato slices in the prepared baking dish. Top with half the onion slices followed by half the cheese sauce. Repeat layering with remaining potatoes, onions, and cheese sauce.
06 - Sprinkle remaining shredded cheeses and paprika evenly over the top layer.
07 - Cover baking dish tightly with aluminum foil. Bake for 40 minutes at 375°F.
08 - Remove foil and bake for an additional 25 to 30 minutes until potatoes are tender and the top achieves a golden brown color.
09 - Allow the dish to rest for 10 minutes before plating to ensure proper setting and optimal flavor distribution.
