Step 1

Preheat oven to 350°F. Line a 12-cup muffin tin with paper liners. Whisk flour, baking powder, cinnamon, baking soda and salt together in a medium bowl. Set aside.

Step 2

Whisk yogurt and peanut butter together in a large bowl until smooth. Add eggs, banana, brown sugar, granulated sugar and vanilla; whisk to combine. Fold the flour mixture into the banana mixture until the flour is mostly incorporated.

Step 3

Spoon the batter evenly into the prepared muffin cups (3 heaping tablespoons each); sprinkle evenly with walnuts. Bake until a wooden pick inserted in the centers comes out clean, 18 to 22 minutes. Remove from oven; let cool for 5 minutes. Serve warm or let cool completely, about 30 minutes.