Preheat oven to 350 degrees and grease a loaf pan with coconut oil.
In a food processor, combine the almond flour, garbanzo bean flour, flax meal, baking soda, and salt. Pulse until blended.
Add the egg yolks, butter, amasai or yogurt, and stevia (if using). Pulse until blended.
Put the egg whites in a large bowl and mix with an electric mixer until soft peaks form.
Pour into the flour mixture in the food processor and pulse (do not run) until the egg whites are blended.
Spread into the greased loaf pan. Bake 40 minutes, or until a toothpick comes out clean.
Cool in the pan for 15 minutes and then cool the rest of the way on a rack.