For the cake:
4 very ripe bananas
2 large eggs
1 tsp. pure vanilla extract
1 ½ cups unbleached all-purpose flour
1 cup granulated sugar
1 tsp. baking soda
2 tsp. ground cinnamon
3/4 cup peanut butter
2 cups chocolate chips
For the topping:
1/4 cup + 2 Tbsp. granulated sugar
1/2 tsp. ground cinnamon
2 Tbsp. brown sugar
Preheat the oven to 375 degrees fahrenheit. Grease a 9x13 square pan. In a medium mixing bowl, mash the bananas well with a fork or potato masher. Add the eggs and vanilla, and stir well to combine. In a separate bowl, mix together the flour, sugar, baking soda, and cinnamon—then add to the banana mixture. Add the peanut butter and when that is combined, add the chocolate chips. Pour the batter into the prepared pan, and set aside. In a small bowl, stir together the cinnamon and granulated sugar. Sprinkle the mixture evenly over the batter in the pan, then sprinkle brown sugar over the top. Bake for 35-40 minutes, or until a toothpick inserted into the center comes out clean. Let cool in the pan on a wire rack for at least 15 minutes before serving.