Prepare cake mix according to package directions;
fold in 1/3 cup of ground orange. Pour into 2
greased and floured 8x1 1/2-inch round cake pans.
Bake according to package directions. Cool 10
minutes. Remove from pans, cool on racks.
For filling; combine sugar, cornstarch, salt,
butter, water, and remaining ground orange. Cook
and stir until mixture thickens and boils; cook 2
minutes more. Cool. Stir in coconut.
Split each cake layer once, making 4 layers. To
assemble, spread layers and top of cake sections
with filling. Spread frosting on sides of cake.
Garnish top with fresh orange slices.