Preheat oven to 200 degrees C (400 degrees F).
Mash Banana (3) using a fork. Combine All-Purpose Flour (1 1/2 cup), Unsweetened Cocoa Powder (1/2 cup), Baking Powder (1 teaspoon), and Baking Soda (1/2 teaspoon). Sieve the mix and keep aside.
To a bowl add Vegetable Oil (3/4 cup), Powdered Confectioners Sugar (1/2 cup), Thick Yogurt (1 tablespoon), and Vanilla Essence (1/2 teaspoon). Beat until well combined. Add mashed banana. To this add sieved all purpose flour mix in batches along with Milk (1/4 cup) and make a smooth ribbon consistency batter.
Add Chocolate Chips (1/2 cup). Fold in the chocolate chips into the batter. Grease the muffin tray or line it with paper liner. I have used individual muffin cups. Fill the cups three fourths with the batter and sprinkle few chocolate chips on top.
Bake for about 20 minutes. After 20 minutes check by inserting a wooden skewer or tooth pick in the center. If it comes out clean then the muffins are ready. Take out the muffins from the oven and let the muffins cool completely on a wire rack. Serve as breakfast, or snack or dessert.