Beat German chocolate cake mix and next 3 ingredients at low speed with an electric mixer 30 seconds or just until moistened; beat at medium speed 2 minutes. Pour batter evenly into a greased and floured 13- x 9-inch baking pan.
Bake at 350° for 32 to 35 minutes or until a wooden pick inserted in center comes out clean. Cool cake completely in pan on a wire rack.
Spread Coconut-Pecan Filling evenly on top of cake.
Note: For testing purposes only, we used Betty Crocker Super Moist German Chocolate Cake Mix.