Cut the eggs in half lengthwise, shell and all. Carefully scoop out the egg whites and yolks with a teaspoon, mash them together, and mix in grated cheese, chopped onion, mustard, salt, and pepper.
Combine this mixture with sour cream. Stuff the egg shells with the filling, sprinkle with breadcrumbs, and fry them in margarine with the filling side down. Serve hot with mashed potatoes and a salad.
Ingredients: 6 hard-boiled eggs, 50g of sharp cheese, 1 teaspoon of mustard, 1 tablespoon of chopped onion, 2 tablespoons of sour cream, ground white breadcrumbs, salt, and pepper.