Preheat oven to 375. Line 2 baking sheets with parchment paper or a silicon baking mat.
Cream together the peanut butter and sugars. Add the mashed banana and mix until creamy.
In a separate bowl, combine the flours, baking powder, and salt. Add the flour mixture to the peanut butter a little at a time until totally absorbed. Add the chocolate chips, if desired, and mix until well-blended, but do not over-mix.
Drop by rounded tablespoons onto prepared pans, about 2 inches apart. Flatten with a fork dipped in water. (These cookies will not spread as they cook, so the shape they’re in when they come out of the oven will be about the same as when they went in.) Bake for about 10 minutes, until bottoms are golden brown. Remove and let cool before serving.
Makes 20 cookies. Each cookie without chocolate chips contains 103 Calories (kcal); 3g Total Fat; 3g Protein; 17g Carbohydrate; 0mg Cholesterol; 64mg Sodium; 1g Fiber.