In medium bowl, mix together dry ingredients (almond flour, coconut flour, xanthan gum, salt, stevia, erythritol, and baking powder).
Add mashed banana, butter, coconut oil, eggs, and vanilla extract into a food processor.
Process until well blended. Add dry ingredients and process until uniform batter is formed.
Mix in chopped walnuts.
Pour batter into a greased 9×5 inch loaf pan.
Bake at 325F and start checking for doneness after a half hour. Remove from oven when top is browned and toothpick inserted comes out dry. This could take anywhere from a half hour to 70 minutes depending on pan size and oven.
Banana extract can be used in place of all or some of the banana to reduce carbs.Less eggs should work. May be able to use only 4 or 5 eggs.Use a low temperature. Turn down the oven temperature a little and bake it for just a little bit longer. Don’t be surprised if you need more time in the oven than the recipe calls for. Simply keep the low-carb banana bread in until it passes the toothpick test and no longer has any soft areas. Make banana muffins. If you want it to cook up faster, another option is making banana muffins with a mix of almond flour and oat fiber. Mmmm - they are so good!Turn this into mini muffins. Consider making these mini keto banana bread muffins, too. It's fun to have a basket of them out for the company to enjoy when you're ready for a treat.