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Ingredients
For the Cake:
- 1¾ cups (220g) all-purpose flour
- 1 tsp baking soda
- ½ tsp baking powder
- ¼ tsp salt
- 1 tsp ground cinnamon
- ½ cup (115g) unsalted butter, softened
- 1 cup (200g) granulated sugar
- 2 large eggs
- 1 tsp vanilla extract
- 1 cup mashed ripe bananas (about 2-3 bananas)
- ½ cup sour cream or plain yogurt
- ½ cup chopped walnuts or pecans (optional)
For the Streusel Topping:
- ½ cup (65g) all-purpose flour
- ⅓ cup (65g) brown sugar
- 1 tsp ground cinnamon
- ¼ cup (55g) cold unsalted butter, cubed
Instructions
- Preheat oven to 350°F (175°C). Grease and flour a 9×9-inch square pan or line with parchment.
- In a bowl, whisk together flour, baking soda, baking powder, salt, and cinnamon.
- In a large bowl, cream butter and sugar until light and fluffy.
- Add eggs one at a time, then vanilla extract.
- Mix in mashed bananas and sour cream until combined.
- Gradually fold dry ingredients into wet until just combined. Stir in nuts if using.
- Prepare the streusel: Mix flour, brown sugar, and cinnamon. Cut in cold butter until crumbly.
- Pour batter into the pan, then sprinkle streusel evenly over the top.
- Bake for 40–45 minutes or until a toothpick inserted in the center comes out clean.
- Cool in the pan for 15 minutes, then transfer to a wire rack.
Tips:
- Use very ripe bananas for best flavor and moisture.
- Serve warm with butter or cream cheese.
- Can be stored in an airtight container for 3 days or frozen for up to 2 months.
