Grease muffin pan with coconut oil. Combine the first 6 ingredients (almond flour through nutmeg) and mix well. To the dry ingredients, add the banana, eggs, honey, and almond butter. Mix until well combined. Fill each muffin 2/3 full, and sprinkle chopped walnuts on each muffin.
Bake for 25 minutes, or until muffins spring back when touched.