Preheat your oven to 350°F (175°C) and line a 12-cup muffin tin with paper liners or grease it lightly.
In a large bowl, mash the ripe bananas with a fork until smooth.
Add the eggs, unsweetened applesauce, vanilla extract, and plain Greek yogurt to the mashed bananas. Mix well until combined.
In a separate bowl, whisk together the whole wheat flour, baking soda, baking powder, ground cinnamon, and salt.
Gradually add the dry ingredients to the wet ingredients, stirring gently until just combined. Do not overmix.
Divide the batter evenly among the 12 muffin cups, filling each about three-quarters full.
Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Remove the muffins from the oven and allow them to cool in the tin for 5 minutes before transferring to a wire rack to cool completely.