Ingredients
1/4 cup butter, cubed1/3 cup all-purpose flour3/4 teaspoon salt1/2 teaspoon ground mustard1/2 teaspoon white pepper2 cups half-and-half cream1-1/2 cups shredded sharp white cheddar cheese1-1/2 cups shredded sharp yellow cheddar cheese6 cups thinly sliced peeled Yukon Gold potatoes (about 2 pounds)2 small onions, finely chopped
Preparation
Preheat oven to 350°. In a large saucepan, heat butter over medium heat. Stir in flour, salt, mustard and pepper until blended; cook and stir 2-3 minutes or until lightly browned. Gradually whisk in cream. Bring to a boil, stirring constantly; cook and stir 1-2 minutes or until thickened. Remove from heat.
In a small bowl, combine cheeses. Layer a third of the potatoes, a third of the onions and 3/4 cup cheese mixture in a greased 3-qt. baking dish. Repeat layers twice. Pour sauce over top; sprinkle with remaining cheese.
Bake, covered, 45 minutes. Uncover; bake 25-30 minutes longer or until potatoes are tender and top is lightly browned.
