Preheat the oven to 350°F. Prepare your muffin tins with muffin liners or nonstick spray and set aside.
In a large bowl or mixing bowl, cream the unsalted butter, white sugar, brown sugar, and eggs using a hand mixer until light and fluffy. Make sure the butter is at room temperature for the best results.
½ cup unsalted butter, ¾ cup granulated sugar, ¾ cup of light brown sugar, 2 large eggs
Add the sour cream, vanilla bean paste, and mashed banana to the bowl and mix until combined. This banana mixture adds moisture and enhances the banana flavor.
¼ cup sour cream, 1 teaspoon vanilla bean paste, 1 cup mashed bananas
In a separate bowl or medium bowl, whisk together the dry ingredients. Add the dry ingredients to the wet ingredients and mix just until combined. Avoid overmixing the muffin batter to keep the muffins tender.
2 cups all-purpose flour, ½ Tablespoon baking powder, ½ teaspoon baking soda
Fold in ¾ cup of the mini chocolate chips, saving the rest for the tops. Divide the batter evenly into the muffin cups, filling each about ¾ full. Sprinkle the remaining chips over the tops.
1 cup mini semi-sweet chocolate chips
Bake for 20–25 minutes, or until the tops are lightly browned and a toothpick inserted into the center of the muffins comes out clean. Allow the muffins to cool slightly, then run a butter knife around the edges to gently release them from the pan.