Separate the egg whites from the yolks. Add Cream of Tartar to the whites and beat until soft peaks are achieved.
In a food processor combine the egg yolks, 1/3 of the beaten egg whites, melted butter, almond flour, baking powder and salt (Adding ~6 drops of liquid stevia to the batter can help reduce the mild egg taste). Mix until combined. This will be a lumpy thick dough until the whites are added.
Add the remaining 2/3 of the egg whites and gently process until fully incorporated. Be careful not to overmix as this is what gives the bread it's volume!
Pour mixture into a buttered 8x4 loaf pan. Bake for 30 minutes. Check with a toothpick to ensure the bread is cooked through. Enjoy! 1 loaf makes 20 slices.