Preheat your oven according to the brownie package directions. Spray a 9-inch square baking dish with baking spray and line it with parchment paper for easy removal.
Prepare the brownie batter according to the package instructions and spread it evenly into the prepared pan.
Scatter patriotic sprinkles over the brownie batter.
Break the softened cookie dough into small pieces and evenly place them over the top of the brownie batter. Don’t press them down too much.
Bake according to the brownie package directions. If the center still looks underdone, continue baking in 2 to 3-minute increments until set.
Let the brownies cool completely before slicing.
Serve each brownie bar topped with a scoop of red, white, and blue ice cream, a drizzle of marshmallow cream, and extra sprinkles.