Step 1

Position an oven rack in the center of the oven and preheat to 350 degrees F. Line a 12-cup muffin pan with paper liners.

Step 2

Whisk the flour, protein powder, baking powder, cinnamon, baking soda and salt in a medium bowl until combined.

Step 3

Whisk the brown sugar, yogurt, coconut oil, vanilla and eggs in a separate large bowl until well combined. Stir in the mashed banana, then the flour mixture until just combined. Fill each paper liner halfway with batter, then top each with 2 teaspoons peanut butter. Top evenly with the remaining batter (the paper liners should be nearly full).

Step 4

Bake until the muffins are golden brown and a toothpick inserted in the center comes out clean, 30 to 35 minutes. Let cool 5 minutes in the pan, then transfer to a wire rack to cool completely. Store in an airtight container for up to 4 days.