Preheat the oven to 350 °F. Lightly grease the baking pan with butter.
In a large mixing bowl, whisk together all dry ingredients except chopped chocolate chunks. Set aside.
In another mixing bowl, mix together the egg replacer and water. Set aside for 5 minutes. Blend together the rest of wet ingredients in a blender until smooth.
Mix wet ingredients and egg replacer-water mixture into the dry ingredients until just combined. Stir in 2 tbs chopped chocolate chunks.
Pour the cake batter into the prepared baking pan. Place the baking pan on the middle rack in the oven and bake for 28 minutes until a toothpick inserted in the center comes out clean. Let the cake totally cool in the pan before garnishing.
While the cake is cooling, mix all frosting ingredients together until smooth. If the coconut cream is runny, refrigerate for at least 1 hour before applying on top of the cake. Pour the frosting on top of the cake and sprinkle with 1 tbs chocolate chunks.
For homemade gluten-free all-purpose gluten free flour, see here.