Melt the butter in a sauce pan over moderate heat and stir in the flour. Cook for 2 minutes, then stir in the milk and cream. Cook, stirring constantly, until the mixture boils and thickens. Stir in the cheese until melted. Remove from the heat and stir in the egg yolks, salt, and pepper. Pour into a well greased 6 x 9 inch (15 x 23 cm) pan and chill for at least 2 hours. Remove from the pan by dipping it in warm water and cut the custard into squares, or into shapes using a cookie cutter. Dredge lightly with flour, dip into the beaten egg, and then coat with bread crumbs. Fry in hot oil until golden brown on both sides, about 3 to 4 minutes. Drain on paper towels and serve immediately.