Preheat oven to 350 degrees. Grease muffin tin or add liners.
In a medium bowl, mix together all of the dry ingredients and set aside.
In a larger bowl, cream together the butter and coconut oil with the sugar and maple syrup.
Add the eggs one at a time and whisk until fully combined.
Add the vanilla and bananas and stir to combine.
Slowly add the dry ingredients to the wet ingredients, alternating with small amounts of buttermilk or yogurt. Continue until you use all of the ingredients.
Scoop dollops of batter into prepared muffin tin.
Bake until golden brown, or about 20 minutes.