1. Grease a 9×13 inch pan, set aside.

2. In a large pot over low-medium heat, melt butter. Once melted, add the marshmallow and stir until completely melted.

3. Remove from the heat and add the Lucky Charms cereal. Stir until all cereal is covered.

4. Pour mixture into prepared pan and press into an even layer. Allow to set until firm, then cut into squares and serve.