Bake the Cupcakes
Prepare cake mix as directed.
Bake 24 cupcakes and let them cool completely.
Frost and Freeze
Spread a layer of cream cheese frosting on each cupcake.
Place frosted tops down on a parchment-lined pan.
Freeze 25–30 minutes, then peel off parchment and flip right-side up.
Smooth the Tops
Dip a butter knife in warm water and gently glide over the tops for a smooth, professional look.
Chill 10 minutes to set.
Decorate with Lights
Pipe a swirly black icing line for the light strand.
Press mini M&Ms (M side down) along the line to make colorful “bulbs.”
Chill & Serve
Refrigerate until ready to serve so the icing stays firm and colors vibrant.