01 - 
                Grease a 9×13 inch baking pan and set aside.
              
              
              
                02 - 
                In a large saucepan, melt the butter over low heat. Add the marshmallows and stir until completely melted.
              
              
              
                03 - 
                Mix in the pink lemonade concentrate and red food coloring (if using), stirring until the mixture is smooth and uniformly pink.
              
              
              
                04 - 
                Remove from heat and fold in the Rice Krispies cereal, lemon zest, and a pinch of salt. Stir until the cereal is well coated.
              
              
              
                05 - 
                Evenly press the mixture into the prepared pan using a buttered spatula.
              
              
              
                06 - 
                Allow the treats to cool for about 30 minutes, then slice into squares.