Heat oven to 350°F / 175°C
Prepare a 12-cup muffin pan with 12 of the tulip liners.
Whisk the AP flour (213g) and baking soda (1tsp) together in a small bowl and set aside.
Brown the butter (70g) and add it and any brown bits to a large bowl.
Add the bananas (227g), the granulated sugar (100g), brown sugar (100g), buttermilk (80g), oil (60g), vanilla (1 tablespoon), and salt. Whisk to combine. If warm, let cool to room temperature.
Add the eggs (2) and whisk until completely combine. (this is why you let the above step cool: you don't want to make scrambled eggs)
Add the flour/soda mixture and stir together.
Evenly distribute the batter to the 12 prepared muffin cups. Should be about ¼- to ⅓-cup each.
Top each muffin with ~2 tablespoons of the crumbly topping. Be wild.
Bake at 350°F / 175°C for 22-28 minutes -- a toothpick should come out clean.