Melt 3 tablespoons butter in heavy saucepan or skillet.
Add garlic and onion; cook until tender but not brown.
Blend in 2 tablespoons flour.
Add beef broth; cook, stirring, until smooth and thickened.
Combine remaining flour, salt and pepper; dredge livers in flour mixture.
Brown livers in remaining butter over high heat; stir into sauce.
Add Madeira; heat through.