Preheat oven to 325 degrees and line a 9x9 inch metal baking pan with parchment paper.
In a large bowl, whisk together the sugar, cocoa powder, flour, xanthan gum, baking soda, salt, and cornstarch.
Make a well in the center and add the eggs. Beat the eggs and mix in the butter, oil, vanilla extract, and water. Mix until the dry ingredients are incorporated.
Transfer the batter to the prepared pan and bake at 325 degrees for 22-25 minutes. Cool completely in the pan before frosting.
Top the completely cooled brownies with the coconut frosting and toasted coconut. Slice into 16 pieces and serve at room temperature.
Notes
I use my Nightshade Free Gluten Free Flour Blend in this recipe. If you use a flour blend that already contains xanthan gum, omit the amount called for in this recipe.
If you like a firmer, more well-done brownie, you can bake them a little bit longer.
The frosted brownies freeze well, just leave off the toasted coconut on top. Slice into individual pieces before freezing. Defrost at room temperature and top with toasted coconut before serving.
Refrigerate the frosted brownies for 30 minutes before before slicing if you want nice clean cuts.