Preheat the oven to 350°F. Grease a loaf pan with butter and lightly dust it with flour.

Peel and mash two very ripe plantains using a fork or potato masher. Set aside.

In a stand mixer, cream the butter and sugar on medium-high speed until pale and fluffy. Reduce the speed to low and mix in the milk for about 1 minute. Add the sour cream and mashed plantains, mixing just until combined.

Crack in the eggs one at a time, mixing gently on low speed after each addition.

In a separate bowl, whisk together the flour, salt, baking soda, baking powder, oats, cinnamon, and nutmeg.

With the mixer on low, add the dry ingredients to the wet mixture in thirds. Let each addition fully incorporate before adding the next. Pause to scrape down the sides of the bowl to make sure everything mixes evenly.

Once the batter is smooth, remove the bowl from the mixer. Use a spatula to scrape along the bottom and sides to ensure there’s no dry flour left.

Toss the chocolate chips in a little flour to keep them from sinking, then fold them gently into the batter. Be careful not to overmix.

Spoon the batter into the prepared loaf pan and level the top with your spatula. Sprinkle a few extra chocolate chips in a straight line down the center.

Bake for 50 minutes, or until a toothpick inserted in the center comes out clean. Let the bread cool in the pan for a few minutes, then transfer to a wire rack to cool completely.

Slice and serve slightly warm or at room temperature.