Step 1

Preheat oven to 350°F (180°C). Line a 12-cup muffin pan with paper liners.

Step 2

In a large bowl, mix together 1 1/2 cups flour, baking soda, baking powder and salt.

Step 3

In the bowl of a stand mixer, beat together sugar and butter for about 4 minutes.

Step 4

Add the egg and vanilla extract, whisk until combined. Stir in the mashed bananas.

Step 5

Add the wet mixture to the dry mixture and mix until just combined.

Step 6

Spoon batter into prepared muffin cups.

Step 7

In a small bowl, combine all-purpose flour, sugar, and cinnamon. Cut in butter until mixture is crumbly. Sprinkle evenly over muffins.

Step 8

Bake for 20 - 25 minutes, until a toothpick, inserted into the center, comes out clean.