# Ingredient List:
→ 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 tbsp unsalted butter
07 - 2 tbsp all-purpose flour
→ Seasonings
08 - 1 tsp salt
09 - 1/2 tsp black pepper
10 - 1/2 tsp garlic powder
11 - 1/4 tsp paprika
# How-To Steps:
01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish with butter or cooking spray.
02 - Melt 2 tbsp butter in a medium saucepan over medium heat. Add flour and whisk continuously for 1 minute until combined.
03 - Slowly pour in 2 cups whole milk while whisking constantly to prevent lumps. Continue cooking for 3-4 minutes until sauce thickens slightly.
04 - Remove from heat. Stir in salt, black pepper, garlic powder, and half of the cheddar and mozzarella cheeses until 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 the baking dish with aluminum foil and bake for 40 minutes.
08 - Remove foil and continue baking for 25-30 minutes until potatoes are tender and the top is golden brown.
09 - Remove from oven and let stand for 10 minutes before serving.