Bake cupcakes according to the instructions on the cake mix box. Allow to cool completely.
Roll out white fondant and use a snowflake cutter to cut snowflake shapes.
Dust the snowflakes with edible shimmer or luster dust and let them dry on parchment paper.
Prepare white buttercream frosting and fill a piping bag with your preferred decorative tip.
Frost each cupcake with a swirl of buttercream.
Gently place a fondant snowflake on top of each cupcake.
Optionally, sprinkle with sparkling sugar for a festive touch.