In a medium saucepan, over low to medium heat, combine the milk chocolate and unsalted butter, stirring until melted and smooth, about 5 minutes. Add the mini marshmallows and stir until fully incorporated.

Remove the saucepan from heat and pour the melted chocolate mixture over a bowl filled with Rice Krispies. Gently combine until the Rice Krispies are evenly coated. Allow to cool for about 10 minutes.

Dampen your hands and take small portions of the mixture to roll into 1-inch balls. Place on a baking tray lined with parchment paper. Refrigerate for about 30 minutes to set.

Melt the white chocolate in a microwave-safe bowl, heating in 30-second intervals until smooth. Drizzle over each pudding using a fork or piping bag.

Use colored sugarpaste to create holly leaves and berries. Roll small pieces into desired shapes and color with food color gel, then press onto the drizzled chocolate.