Prep your pan and oven. Heat the oven to 375°F (190°C). Line a 12-cup muffin pan with paper liners or grease well. This helps the muffins release cleanly and brown evenly.

Mash the bananas. In a large bowl, mash the bananas with a fork until mostly smooth. A few small lumps are fine and add texture.

Whisk in the wet ingredients. Add the granulated sugar, brown sugar, oil, eggs, yogurt or sour cream, and vanilla. Whisk until the mixture looks cohesive and glossy.

Combine the dry ingredients. In a separate bowl, whisk together the flour, baking powder, baking soda, salt, and optional spices. This prevents clumps and ensures even lift.

Bring it together. Add the dry ingredients to the wet. Stir gently with a spatula until just combined. Stop as soon as you no longer see dry flour to avoid tough muffins.

Fold in the chocolate chips. Use a few light strokes to distribute them evenly. You can reserve a handful to sprinkle on top.

Fill the muffin cups. Divide the batter evenly among the 12 cups, filling each about 3/4 full. Sprinkle reserved chips or coarse sugar over the tops if using.

Bake. Place the pan on the middle rack and bake for 16–20 minutes, until the tops are set and lightly golden. A toothpick should come out clean or with a few moist crumbs (melted chocolate doesn’t count).

Cool. Let the muffins rest in the pan for 5 minutes, then transfer to a wire rack. Cool to warm for serving, or to room temperature for storage.