Begin by greasing a 9x13 inch baking dish with a touch of oil or butter to prevent sticking.

In a large saucepan over low heat, melt the 3 tablespoons of butter. Stir it occasionally to ensure it doesn’t burn.

Once the butter is melted, add the full package of marshmallows to the saucepan. Continuously stir until the marshmallows are completely melted and the mixture is smooth.

Remove the saucepan from heat and mix in the lemon zest and lemon juice.

Gradually fold in the 6 cups of Rice Krispies cereal, coating all the cereal evenly.

Pour the mixture into the prepared baking dish. Using a greased spatula or wax paper, press the mixture firmly and evenly into the pan.

Let the treats cool for about 30 minutes before slicing them into squares.

If desired, dust lightly with powdered sugar before serving.