Prepare the Pan:
Grease a 9×13-inch baking pan with butter or non-stick spray. Set aside.
Melt Butter and Marshmallows:
In a large saucepan over low heat, melt the butter. Add the marshmallows and stir until they are completely melted and smooth.
Add Pink Lemonade Mix:
Stir in the powdered pink lemonade mix and a few drops of red food coloring (if using) to achieve a uniform pink color. Continue stirring until fully combined.
Mix in Rice Krispies:
Remove the pan from the heat. Add the Rice Krispies cereal, lemon zest (if using), and a pinch of salt. Stir until the cereal is fully coated with the marshmallow mixture.
Press into the Pan:
Using a buttered spatula or a piece of wax paper, evenly press the mixture into the prepared pan. Allow to cool for at least 30 minutes.
Cut and Serve:
Once cooled, cut the treats into squares or desired shapes and serve.