# Components:
→ Vegetables
01 - 2.5 pounds russet or Yukon Gold potatoes, peeled and thinly sliced
02 - 1 small yellow onion, thinly sliced
→ Dairy
03 - 2 cups whole milk
04 - 1 cup heavy cream
05 - 2 cups sharp cheddar cheese, shredded
06 - 1 cup Gruyère or Monterey Jack cheese, shredded
07 - 4 tablespoons unsalted butter
→ Pantry & Spices
08 - 3 tablespoons all-purpose flour
09 - 1 teaspoon garlic powder
10 - 1 teaspoon salt, plus additional to taste
11 - 0.5 teaspoon ground black pepper
12 - 0.25 teaspoon smoked paprika
# Method:
01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish with butter.
02 - Melt butter in a medium saucepan over medium heat. Whisk in flour continuously for 1 to 2 minutes until bubbly but not browned.
03 - Gradually whisk in whole milk and heavy cream. Continue whisking for 3 to 5 minutes until sauce thickens.
04 - Stir in garlic powder, salt, black pepper, and smoked paprika. Remove from heat.
05 - Add 1½ cups cheddar and ½ cup Gruyère cheese. Stir until fully melted and smooth.
06 - Place half the sliced potatoes in an even layer in the baking dish. Top with half the onions.
07 - Pour half of the cheese sauce over potatoes and onions. Repeat layering remaining potatoes and onions, then cover with remaining sauce.
08 - Sprinkle remaining cheddar and Gruyère evenly over the top.
09 - Cover dish tightly with foil and bake for 45 minutes.
10 - Remove foil and continue baking 25 to 30 minutes until potatoes are tender and top is golden and bubbling.
11 - Allow to rest for 10 minutes before garnishing with chopped chives or parsley and serving.
