Line a 9 by 9 inch baking pan with parchment or wax paper cut so that it sticks up over the edges of the pan by a couple of inches on each side.
In a saucepan, melt 1 cup of Sunbutter and the butter. Stir until smooth and remove from the heat. Stir in graham style crumbs, powdered sugar, and vanilla until well combined. Pour the mixture into the prepared pan and smooth the top.
Combine the remaining ¼ cup of Sunbutter and the chocolate chips in a microwave-safe bowl. Microwave for 1 minute, stir and if the Sunbutter is not fully melted, continue to microwave fat 20 second intervals, stirring after each 20 seconds. Once smooth, pour the mixture over the Sunbutter layer and smooth the top. Cover the chocolate layer with the marshmallows. Preheat the broiler broil for about 1 minute or until the marshmallows start to brown. Refrigerate for 20-30 minutes to set up. Remove from the pan, cut into 16 bars (2¼ inches by 2¼ inches). Serve or store in the refrigerator, covered.