Potato Puff Casserole Recipe
Ingredients 1 small onion, chopped2 tablespoons butter1/2 cup whole milk1/2 teaspoon ground mustard1/4 teaspoon salt1/8 teaspoon pepper2 cups mashed potatoes (with added milk and butter)2 large eggs, separated1 cup shredded cheddar cheese, optional Preparation In a large skillet, saute onion in butter until tender. Stir in the milk, mustard, salt and pepper; bring to a boil. Remove from the heat; stir in potatoes. Stir in egg yolks until blended. Cool at room temperature for 15 minutes....