3 oz semi-sweet chocolate baking squares, coarsely chopped
Preheat oven to 350 degrees.
In a medium bowl, whisk together flour, graham cracker crumbs, baking soda, cinnamon and salt.
In a large bowl, combine banana, peanut butter, yogurt, butter and eggs; beat with an electric mixer on medium speed until smooth. Add sugar and beat until well blended.
Add flour mixture; beat on low speed just until combined.
Place chocolate squares in a medium microwave-safe bowl. Microwave on high power 30 seconds; stir. Microwave 30 seconds longer; stir until smooth. Cool slightly.
Add 1 cup of bread batter to melted chocolate, stirring just until combined.
Spread half of plain batter into a 9x5-inch loaf pan coated with cooking spray. Top with half of chocolate batter. Repeat layers. Swirl batters together using a knife or wooden skewer.
Bake 1 hour and 5 minutes to 1 hour and 15 minutes or until a wooden skewer inserted into the center comes out clean. Cool in pan 10 minutes. Remove from pan and cool completely on a wire rack before cutting into slices.
Recipe by The eMeals Blog at http://blog.emeals.com/banana-bread/