In a large pot melt butter over low heat. Stir in marshmallows until completely melted. Remove from heat.
Use a buttered spatula to stir in Lucky Charms cereal until fully coated.
Press cereal mixture into a greased 13x9 inch pan. Cool.
Cut into squares and remove from pan.
Over a double boiler melt white chocolate; remove from heat.
Dip bottom of cereal treat into the melted chocolate; place on a wax paper covered baking sheet.
Allow chocolate to cool and enjoy!