Heat your oven to 350°F (175°C) and line a muffin tin with paper liners or lightly grease the muffin cups with butter.
Mash the bananas in a small bowl and set aside.
1 cup banana
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
2 cups (250 grams) all-purpose flour, 1 teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon salt
Beat the butter and sugar together using a hand or stand mixer until light and fluffy, about five to seven minutes.
8 tablespoons (113 grams) unsalted butter, 1 cup (200 grams) granulated sugar
Add the eggs one at a time, beating for one minute after each addition. Mix in the mashed bananas, sour cream, and vanilla.
2 large eggs, 1 teaspoon vanilla extract, ¼ cup (60 grams) sour cream
Add the dry ingredients to the wet mixture, stirring gently. Mix until just combined and no traces of the dry ingredients remain.
Stir in the chocolate chunks by hand., then scoop the batter into the prepared muffin tin, filling each cup about three-quarters full.
1 cup (120 grams) chocolate chunks
Bake for 18 to 20 minutes in the center of your oven, until the banana muffins are just lightly browned and a toothpick inserted into the center of one comes out with just a few moist crumbs.
Let the muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely. Or eat one warm—no judgment!