Melt 1/4 cup butter in a heavy saucepan over low heat; add flour, stirring until smooth. Cook 1 minute, stirring constantly. Gradually add milk and half-and-half; cook over medium heat, stirring until thickened and bubbly. Add cheese, stirring until cheese melts. Stir in seasonings and garlic.
Spread one-third of sauce in bottom of a greased 13- x 9- x 2- inch baking dish. Layer half of sliced eggs and half of crumbled bacon over sauce. Repeat layers, ending with sauce.
Combine breadcrumbs and melted butter; sprinkle over casserole. Bake at 350° for 25 minutes or until bubbly and browned. Serve hot.