Blend first five ingredients together, and set aside one cup of this mixture as a topping base for use later. In separate bowl, mix the eggs, buttermilk and baking soda together. Then blend the remaining portion of the original crumb mixture, stirring thoroughly. There will be some small lumps in the batter. Add 1 cup brown sugar, 1/2 cup coconut and 1 teaspoon cinnamon to the cup of original crumb topping mixture, set aside earlier. Pour coffee cake batter mixture into 3 greased and floured 8" cake pans. Sprinkle topping equally on top of batter in all 3 pans. Bake at 350 ° for 35 minutes.
