Preheat the oven to 350 degrees Fahrenheit.
Add the whole wheat flour or spelt flour and baking powder to a mixing bowl, then mix well.
Add the bananas to a second mixing bowl, then use a potato masher or fork to mash them well.
Add the almond butter, unsweetened plant-based milk, coconut sugar, vanilla extract, cinnamon, nutmeg, and salt to the bowl with the mashed bananas, then use a whisk to mix well.
Add the dry ingredients to the wet ingredients, then stir to combine.
Add the blueberries, then gently stir to combine.
Divide the batter evenly into a 12 cup muffin pan lined with paper baking cups.
Bake at 350 degrees Fahrenheit for 30 minutes or until a toothpick inserted into a muffin comes out looking clean.
Let the muffins cool to room temperature before removing from the pan and serving.