Beat first 4 ingredients at medium speed with an electric mixer 2 minutes. Stir in coconut and pecans. Pour batter into 3 greased and floured 9" round cake pans.
Bake at 350° for 15 to 17 minuts or until a wooden toothpick inserted in center comes out clean. Cool in pans on wire racks 10 minutes. Remove from pans and cool completely on wire racks. Sprinkle cake layers evenly with rum, if desired; let stand 10 minutes.
To make Cream Cheese Frosting: Beat cream cheese and butter at medium speed with an electric mixer until smooth. Gradually add powdered sugar, beating until light and fluffy. Stir in pecans and vanilla. Makes 4 cups.
Spread Cream Cheese Frosting between layers and on top and sides of cake. Garnish, if desired. Chill 2 hours before slicing.