Preheat the oven to 350 degrees F. You can either use a 9x5 loaf pan (lined with parchment paper) for a loaf or I like to just make muffins with a Silicon muffin baking pan.
Mix dry ingredients in a large bowl; almond flour, coconut flour, baking powder, cinnamon and sea salt.
Put butter and xylitol or erythritol in a food processor or blender or blend with a hand mixer until it's fluffy.
Put the eggs in and blend then put in the banana (or banana extract) and heavy cream (or almond milk).
Pour the dry ingredients into the wet and blend until a moist dough forms.
Spoon the dough into the muffin pan (or loaf pan) and smooth the top as almond flour doesn't spread and smooth on its own when warm like wheat flour.
Bake for 30 minutes or until you can put a toothpick in and it comes out with no dough on it.Let them cool or they will fall apart on you, but if you can't wait then just eat it with a spoon :)