Preheat the oven to 400°F and lightly grease 16 muffin cups or use paper liners.
In a medium-sized bowl, whisk together flour, baking powder, baking soda and salt. Set aside.
In a large mixing bowl, cream the butter and sugar together with a handheld or stand mixer until light and fluffy. Scrape down the bowl to make sure all the butter is incorporated, then add the eggs, one at a time, beating well after each addition.
Add the vanilla and sour cream and mix until incorporated.
Add the dry ingredients and mix on low-speed just until the batter is smooth. Add diced bananas and coconut and stir just to incorporate.
Fill the muffin tins and bake for 18 to 24 minutes or until a tooth pick inserted in the center comes out clean.
Remove the muffins from the oven, cool in the pan for 5 minutes and then remove the muffins from the pan to finish cooling on a rack. Muffins left in the pan to cool the entire time will become tough from steaming.
Recipe by Sprung At Last at https://sprungatlast.com/2013/03/banana-coconut-muffins/