Spray Two (8-inch) round cake pans with cooking spray; dust bottom and sides with flour. Set aside.
Combine flour, baking powder, baking soda, salt, and cinnamon in a small bowl. Set aside.
Beat eggs, vegetable oil, and Splenda Sugar Blend for Baking at medium speed with an electric mixer until batter is smooth. Add flour mixture beating at low speed until blended. Fold in carrots, pineapple, walnuts, and coconut.
Pour batter into prepared cake pans.
Bake for 35 to 40 minutes, or until a toothpick inserted in center comes out clean. Cool in pans on a wire rack 10 minutes. Remove from pans, and let cool completely.
To make the frosting: Place frosting ingredients in a mixing bowl. Mix on medium speed until well blended. Ice cake when cake is completely cool.
Optional garnish: Sprinkle finely chopped walnuts over the top of the cake.