Preheat the oven to 350°F then lightly grease a 9x5 inch loaf pan.
In a large bowl, whisk together the spelt flour, cinnamon, baking powder, baking soda, and salt.
In a separate bowl, add the mashed banana, maple syrup, vanilla, and almond butter. Stir together until smooth.
Add the dry ingredients to the bowl with the wet and fold everthing together until a batter forms. Stir in any desired mix-ins such as chocolate chips, chopped nuts or dried fruit. Transfer the batter to the loaf pan.
Bake in the oven for about 45 minutes, or until golden brown on edges and set in the center. Allow to cool completely before serving. Leftovers can be stored in an airtight container in the refrigerator for up to 4 days.
I've tested this with almond butter that only has 2 ingredients (almond butter and salt) as well as almond butter with added oil. The one with oil adds a little more moisture but they will both work for this recipe.