Preheat oven to 425°F and line a 12-cup muffin tin with papers.
To make the topping, stir the flour, brown sugar, cinnamon, and salt together in a small bowl. Add the melted butter and stir until the dry ingredients are evenly saturated. Place the bowl into the fridge to chill while you make the batter.
Place the bananas into a large mixing bowl, then mash them well using a fork or potato masher.
Add the sugar, oil, molasses, milk, and vanilla to the bowl with the mashed banana. Whisk the mixture well until the ingredients are combined. Set this aside for now.
In a separate small mixing bowl, whisk together the flour, ginger, cinnamon, cloves, baking soda, and salt.
Add the flour mixture to the bowl with the banana mixture. Stir just until the ingredients are combined and there are no longer flour streaks in the batter, being careful not to overmix.
Fold the pecans and chocolate chips into the batter.
Divide the batter among muffin cups, then sprinkle the streusel over each muffin, gently pressing it into the batter.
Bake the muffins for 8 minutes, then turn the oven temperature down to 350°F and bake them for 12 to 14 minutes longer, until the tops are domed and feel set, and a toothpick inserted into the center of a muffin comes out clean of batter.
Transfer the tin to a cooling rack and allow the muffins to cool completely before removing them from the tin.