In a large saucepan, melt butter over low heat.
Add the miniature marshmallows and stir until completely smooth and melted. Remove from heat.
Add the Rice Krispies cereal. Stir until well coated.
Use a spatula coated in cooking spray (I use butter flavored spray) to spread into a buttered 13 x 9 pan. Press the mixture evenly and firmly into the pan.
Cool completely.
Melt the white and semi-sweet chocolate chips in separate microwave safe bowls in 30 second intervals, stirring in between until smooth.
Using a Mickey-shaped cookie cutter, cut shapes out of the pan of Rice Krispie treats. Press firmly!
Partially dip each treat into the chocolate, place on a wire rack with wax paper underneath to catch anything that drips off.
Using a spoon, drizzle the white chocolate over the treats.
Decorate with festive M&Ms before the chocolate sets.
Once the chocolate has hardened up, these can be stored in an airtight container for a couple of days, but they are at their absolute best right after making.
