Preheat the oven to 325ºF. Combine the coconut flour, flax meal, arrowroot powder, onion powder, baking powder, baking soda, salt, and 2 tablespoons of the sesame seeds in a large bowl. In a separate bowl, combine the eggs and sour cream. Beat the wet ingredients into the flour mixture. Add the melted butter and beat to combine.
Pour into a 9×5-inch loaf pan and sprinkle the top with the remaining 1 tablespoon of sesame seeds. Bake 40-50 minutes or until cooked through in the center. Cool completely before slicing. (This bread also toasts well.)