Prepare and bake cake mix according to package directions for two 9 inch round pans, except substitute brewed coffee for the water. Cool cakes completely.
Make the Filling: In a saucepan over medium heat, combine butter and evaporated milk. Bring to a boil.
Add the marshmallows and stir until melted and smooth. Stir in coconut.
Place bottom layer on serving plate.
Spread with entire coconut filling. Cover top and sides with fudge frosting. Refrigerate.
