SWISS CHEESE CROQUETTES

Melt 3 tablespoons of butter, add a few drops of onion juice, ¼ cup of flour, ½ cup of milk, the yolks of 2 eggs, 1 cup of grated American cheese, and ½ cup of Swiss cheese cut into small pieces. Let cook in a double boiler until the cheese is melted, then season with salt and cayenne; let cool, then shape into croquettes, roll in crumbs, and fry in deep fat.