In a large bowl, mash bananas then mix in melted butter, maple syrup, egg, and vanilla extract. Then slowly mix in the gluten free flour, baking soda, and salt. Once combined, fold in chocolate chips. Pour mixture into greased bread pan.
Top the batter with graham crackers throughout, then add marshmallows and chocolate chips on top.
Place in the oven to bake for 1 hour-1 hour and 15 minutes, until a toothpick comes out clean from the middle and marshmallows have browned. Let rest for 10 minutes before removing from bread pan and slicing into 8-10 slices!