Servings: 16 muffins Preparation time: 13 minutes
Sift coconut flour, cocoa, baking soda and salt (if using) into a bowl. Set aside.
Combine butter and sugars in an electric mixer fitted with a paddle attachment. Beat on medium speed until light and fluffy, about 1 minute. Beat eggs in one at a time, mixing well after each addition. Mixture will look somewhat "watery". Scrape bowl down with a large rubber spatula if/as needed. Use a fine grater, grate the brazil nuts and dump that into the batter. Add the zest.
On low speed, beat about half of the cocoa mixture into the butter mixture. Stop mixer and scrape bowl and paddle down with rubber spatula. Add mashed bananas and sour cream and mix well. Beat in remaining cocoa mixture and scrape bowl and beater down again.
Remove bowl from mixer and give the batter once last stir with the spatula. Batter will be thick.
Fill muffin tins full (or almost full) with batter and bake until risen and firm to the touch, 24-30 minutes. If a toothpick is inserted into the center it should come out almost clean but with a few tiny crumbs attached.
Let muffins cool in pans for 2-3 minutes before moving to a wire rack. Enjoy!
Based on a recipe by Sarah Shilhavy