Grease a 9×13 inch baking dish or line with parchment paper.<br>2. Melt butter in a large saucepan, add marshmallows and stir until melted.<br>3. Remove from heat, stir in lime zest, juice, and food coloring.<br>4. Add Rice Krispies, stir until well coated, press into dish, top with crushed graham crackers, and let set.
