Preheat the oven to 350°F. Line a 9 x 13 inch baking dish with foil. Set aside.
For the graham cracker layer:
Whisk together flour, cinnamon, baking soda, and baking powder. Set aside.
Stir together melted butter and honey, and stir into the flour mixture. Mix well.
Pat the dough into the lined baking dish in a thin layer, making sure to completely cover the bottom of the baking dish. {It might look thin but it will be good once it bakes.}
Bake in preheated oven for 6 minutes. Remove from the oven and set aside.
For the brownies:
Meanwhile, put the black beans, spinach, and eggs in the bowl of a food processor and process until completely smooth. {You want there to be absolutely no chunks of beans or spinach!}
Add the oil, sugar, cocoa powder, vanilla extract, instant coffee powder, baking powder, and salt. Process until completely combined.
Pour batter over partially baked graham cracker layer.
Bake in the preheated oven for 22 minutes.
Take out of the oven and sprinkle with chocolate chips. Put back in the oven for 5 minutes. Remove from oven and use a spatula to spread the chocolate chips in a thin layer over the brownies.
Sprinkle the entire pan with marshmallows. Turn oven to broil and broil for 1 minute {watch them carefully!} until marshmallows are lightly browned.
Let cool for about 20-30 minutes before slicing. Enjoy!
Notes
Optional: use ¼ sugar + ½ cup sugar substitute if desired*Recipe tested uses white whole wheat flour, but you can use a whole grain gluten free flour if desired.