1. Preheat oven to 350°F (180°C). Mist 12-count muffin tin with cooking spray. Set aside.
2. Whisk together flour, sugar, coconut, baking soda, baking powder and salt in large bowl. Set aside.
3. Whisk together bananas, kefir, coconut oil and vanilla in separate large bowl. Add to flour mixture; stir just until no white streaks remain.
4. Divide among the wells of prepared muffin tin. Bake until tops are golden and toothpick inserted in centres comes out clean; about 30 minutes. Let cool in muffin tin for 15 minutes.
Chef's tip: To freeze muffins, let them cool completely on a rack, then transfer to an airtight container or resealable freezer bag and freeze for up to one month. For extra protection against freezer burn, you can wrap the muffins individually in plastic wrap or foil before placing in the container or bag. Thaw muffins in the fridge overnight or microwave straight from frozen until warmed through; about 20 to 30 seconds.