01 - 
                Get your oven going at 350°F (175°C).
              
              
              
                02 - 
                Use a food processor to grind graham crackers into crumbs until fine.
              
              
              
                03 - 
                Combine the crumbs with sugar and melted butter in a bowl. Stir until blended.
              
              
              
                04 - 
                In a 9x13-inch dish lined with parchment, press the graham mixture down completely.
              
              
              
                05 - 
                Mix the brownie batter as explained on the package.
              
              
              
                06 - 
                Spread the brownie batter evenly across the prepared crust.
              
              
              
                07 - 
                Pop the dish into the oven and bake for 22-25 minutes. The center should feel firm.
              
              
              
                08 - 
                Scatter the chocolate chips and marshmallows over the cooked brownies right away.
              
              
              
                09 - 
                Switch to broil and toast the marshmallows in the oven for about 3 minutes until golden. Watch them closely so they don’t burn.
              
              
              
                10 - 
                Let everything chill out before slicing and digging in.