Preheat your oven to 350 degrees.
In the bowl of a standing mixer, add the ripe bananas, sugar, eggs, melted butter, and vanilla. Using the paddle attachment, mix them together for about a minute to break up any large pieces (you can also use a hand mixer if you want).
Sift together the flour, baking soda and salt and add about half into the bowl with the banana mixture. Mix for a few seconds, and add the Greek yogurt.
Add the rest of your dry ingredients and mix on low, just until the dry ingredients are incorporated. Do not overmix! Small lumps of banana are ok.
Gently fold in the mini chocolate chips with a spatula, if using.
Grease muffin tins (even non-stick) using baking spray or butter, and spoon the batter in, filling them about ⅔ full.
Bake at 350 degrees for 20-25 minutes or until lightly golden brown. Use a cake tester or toothpick to check if they are baked through. You may want to rotate your pan halfway through baking.
Remove from the oven and let cool slightly before removing from the baking tins to cool completely. Enjoy!