Preheat your oven to 375°F (190°C). Line a muffin tin with paper liners or grease the muffin cups.

In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, brown sugar, baking powder, baking soda, and salt.

In another bowl, mix together the peanut butter, melted butter, mashed bananas, eggs, and vanilla extract until well combined.

Pour the wet ingredients into the dry ingredients. Gently fold the mixture together until just combined. Avoid overmixing; a few lumps are okay.

Gently old in the chocolate chips until evenly distributed in the batter.

Spoon the batter into the prepared muffin cups, filling each one ⅔ full.

Bake in the preheated oven for 20 minutes or until a toothpick inserted into the center comes out clean. The tops should be golden brown.

Allow the muffins to cool in the pan for a few minutes, then transfer them to a wire rack to cool completely.