01 - 
                Preheat the oven according to the brownie mix or recipe instructions. Line a 9x13-inch baking pan with parchment paper, leaving an overhang for easy removal. Prepare brownie batter as directed, then evenly spread it into the pan for uniform baking.
              
              
              
                02 - 
                Bake in the preheated oven for 30 to 45 minutes, testing doneness with a toothpick inserted in the center. The toothpick should come out with moist crumbs but no wet batter. Avoid overbaking to maintain a fudgy texture.
              
              
              
                03 - 
                Allow brownies to cool in the pan for 10 minutes. Using the parchment overhang, transfer the slab to a wire rack and cool completely, approximately 1 to 2 hours, ensuring frosting will adhere properly and decorations remain vibrant.
              
              
              
                04 - 
                Divide vanilla frosting into separate bowls according to desired colors. Add 1-2 drops of gel food coloring per bowl and mix thoroughly until color is uniform and vibrant.
              
              
              
                05 - 
                Spread colored frosting over cooled brownies using an offset spatula or butter knife. Create textures like fur or scales by stippling or swirling. While frosting is still tacky, press candy eyes, sprinkles, and optional decorations onto the surface to form monster features.
              
              
              
                06 - 
                Cut decorated brownies into squares or rectangles with a warm, damp knife for clean edges. Arrange on a serving platter and present immediately for best visual impact and freshness.