Preheat the oven to 375F. Line a muffin pan with 16 liners and gently spritz each liner with oil.
In a small bowl, make the crumble. Add the flour, sugar, and salt, then whisk to combine. Cube the butter and pinch into the flour mixture until quarter sized. Add the almond extract and continue to pinch until pea-sized. Place the bowl in the fridge until ready to use.
In a large bowl, mash the bananas with a fork. Add the egg, sugars, yogurt, and sourdough starter and whisk until full combined. Stream in the oil and whisk until the texture is smooth and combined.
In a medium bowl, add the flour, baking powder, baking soda, cinnamon, and salt and whisk thoroughly.
Add the flour mixture to the wet mixture bowl and fold in with a spatula until just a few dry streaks are left. Add the milk, chocolate chips, and berries and continue to fold until just combined. Evenly distribute the batter into the liners, then place a tablespoon of the cold crumble over each muffin. The batter will come up high in the liners.
Bake for 14-16 minutes or until a toothpick comes out clean. Let cool in the pan for 10 minutes then move the muffins to a cooling rack. Enjoy! Let me know what you think below in the comments or on Instagram @higheralchemybaking!