Preheat oven to 350°F. Grease a baking sheet with cooking spray.
In a medium bowl, mix together peanut butter, melted butter, granulated sugar, brown sugar, eggs, bananas, and vanilla until combined.
In a separate bowl, whisk together flour, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients and mix until combined.
Fold in the chocolate chips.
Form dough into two logs, about 12 inches long and 2 inches wide, and place on the prepared baking sheet. Bake for 25 minutes, or until golden brown.
Remove from oven and let cool for 10 minutes. Cut logs into 1/2-inch slices and place cut-side down on the baking sheet. Bake for an additional 10 minutes, or until crisp.
Cool biscotti on a wire rack and store in an airtight container.
Interesting Facts
The original biscotti recipe calls for anise seeds, but any type of nut or seed can be used for an extra crunch.
Biscotti can be stored in an airtight container for up to two weeks.
Biscotti are traditionally dipped in coffee or tea before eating.