- 1 cup white sugar
- 1/2 cup unsalted butter, softened
- 2 large eggs
- 1 teaspoon vanilla extract
- 3 ripe bananas, mashed
- 1 tablespoon milk
- 1 teaspoon allspice
- 2 cups all-purpose flour
- 1 teaspoon baking powder
- 1 teaspoon baking soda
- 1 pinch salt
- 1/2 cup old-fashioned oats
- 1/2 cup chopped walnuts
- Preheat oven to 325 degrees F (165 degrees C). Line 12 muffin cups with papers liners.
- Beat sugar and butter with an electric mixer in a large bowl until smooth and creamy. Beat first egg into the butter until completely blended; beat in the vanilla extract with the remaining egg.
- Mix bananas, milk, and allspice together in a separate bowl; stir into the creamed butter mixture. Whisk flour, baking powder, and baking soda together in a separate bowl; slowly stir into banana-butter mixture until batter is just mixed. Fold oats and walnuts into batter. Scoop batter into the muffin cups using a large ice cream scoop.
- Bake in the preheated oven until a toothpick inserted in the center comes out clean, 25 to 35 minutes.