Mash the bananas until mostly smooth with some small chunks remaining. Measure out all dry ingredients and whisk them together in a medium bowl to distribute the leavening agents evenly.

Prepare the streusel topping by combining ¾ cup flour, brown sugar, cinnamon, and salt in a separate small bowl. Cut the cold butter into ½-inch cubes and add to the streusel mixture, then work it into coarse crumbs.

Preheat your oven to 425°F.

In a large bowl, combine the mashed bananas, vegetable oil, room-temperature eggs, and vanilla. Whisk vigorously for about 1 minute until well combined and slightly emulsified.

Pour the dry ingredient mixture into the wet mixture, folding everything together with as few strokes as possible until flour streaks disappear. Fold in the chocolate chips and let the batter rest for 15 minutes.

Place paper liners in every other hole of a standard muffin pan, fill each about three-quarters full with batter, and top with the streusel mixture and extra chocolate chips.

Bake at 425°F for 7 minutes, then lower the temperature to 350°F and bake for 16-18 minutes longer.

Let the muffins cool in the pan for 5 minutes before transferring to a wire rack for at least 20 minutes.

These muffins are best eaten the same day but will keep in an airtight container for 2-3 days.