Gather your ingredients and butter a 9×13 inch pan. Set aside. Melt butter in a large saucepan.
Add marshmallows and stir frequently over low heat until melted.
Remove from heat and stir in cereal until well coated.
Quickly stir in both chocolate and peanut butter chips.
Using wax paper or a buttered spatula, press mixture into prepared pan. Let cool and cut into 2 inch squares.