Blend the cottage cheese until completely smooth. In a large bowl, whisk the blended cottage cheese, melted butter, brown sugar, egg yolk and vanilla until glossy.
Add the flour, graham cracker crumbs, protein powder, baking soda, cinnamon and salt, and stir until combined. Fold in the milk chocolate chunks, then cover and chill for 30 minutes so the graham crumbs soak up moisture.
Preheat the oven to 350°F and line 2 baking sheets with parchment paper. Scoop the dough into 14 balls, about 2 tablespoons each, and place them 2 inches apart.
Bake for 8 minutes, until the edges are just starting to set.
Remove the baking sheets and quickly press a few mini marshmallows, a piece of milk chocolate and a piece of graham cracker onto each cookie. Return to the oven for 3 to 4 minutes, until the marshmallows are puffed and soft.
For toasted campfire-style tops, broil for 30 to 60 seconds, watching closely. Cool on the baking sheets for 10 minutes, then move to a wire rack. Enjoy slightly warm for melty marshmallows and chocolate.