Preheat the oven to 375 degrees Fahrenheit. Line a muffin tin with paper liners. This makes 14 muffins so you will need 2 muffin tins.
In a medium bowl, combine the flour, baking powder, baking soda, cinnamon and salt. Set aside.
In a large bowl, stir together the melted butter and the brown and granulated sugar until well combined.
Stir in the eggs, mixing well. Add the vanilla extract and Greek yogurt and mix until combined.
Stir in the mashed bananas and shredded carrots.
Add the dry ingredients into the wet ingredients and mix until just combined and no dry flour remains. Do not overmix.
Scoop the batter into the prepared muffin tins, filling them almost to the top.
Sprinkle a heaping teaspoon of granola onto each muffin top.
Bake for 18-20 minutes until a toothpick inserted into the center comes out with moist crumbs but no wet batter.
Let the muffins cool in the pan for about 10 minutes and then they can be removed to cool completely or enjoy slightly warm.