Preheat oven to 180°C (350° F).
Mash the bananas. In a bowl, whisk eggs, mashed bananas, vanilla extract, brown sugar, greek yogurt and melted coconut oil.
Add whole wheat flour, baking powder, baking soda and mix until well-combined. Add chocolate chips and mix.
Pour batter into greased muffin tin (or use muffin liners).
Bake for 30 minutes. Remove from oven, let cool completely and store for up to 6 days or freeze for a month.
Tip: warm the muffins for few minutes in the oven each time before consuming for a fresher texture or microwave.