Step 1

Preheat the oven to 350ºF. Line a muffin tin with paper liners.

Step 2

Mash the bananas well. You'll need one cup mashed bananas. If you have slightly less than one cup, you can use slightly more yogurt to make up for the banana. If you have slightly more than one cup, you can reduce the yogurt slightly to compensate for the extra banana.

Step 3

Add the mashed banana to a large mixing bowl along with the yogurt, eggs, sugar, melted butter, and vanilla. Whisk the ingredients together well.

Step 4

In a separate bowl, stir together the flour, cocoa powder, baking powder, baking soda, and salt.

Step 5

Pour the dry ingredients into the bowl with the wet ingredients and stir just until they are combined. It's okay if the mixture is a little lumpy. Do not over stir. Finally, fold the chocolate chips into the batter.

Step 6

Divide the batter between the 12 wells of the muffin tin (it will fill each well up to the top). Transfer the muffin tin to the preheated oven and bake for 35 minutes.

Step 7

After baking, remove the muffins from the tin and allow them to cool on a wire rack before serving.