Preheat the oven to 350 degrees F. Line an 8x8 square pan with parchment paper.
Combine the graham cracker crumbs, gluten free flour blend, buttery spread, and sugar in a food processor and pulse until a dough forms.
Press the crust into the pan, and bake at 350 degrees F for about 15-18 minutes.
Remove the pan from the oven, and raise the heat to 375 degrees F.
Sprinkle the chocolate chips over the crust, and then do the same with the marshmallows.
Bake at 375 degrees F for 5-7 minutes, until the chocolate is melted and the marshmallows are golden brown.
Let cool somewhat before slicing.
Notes
You can use gluten free graham crackers, like Kinnikinnick brand, or vegan graham crackers, or any brand that suits your needs. Enjoy Life makes a Honey Graham crunchy cookie that would also work.If you don't have special dietary needs, go ahead and use dairy butter, regular flour, dairy chocolate chips, etc.