Preheat the oven to 350°F (180°C). Line 2 baking sheets with parchment paper.
2. Step
In a medium bowl, stir together the cookie mix, butter, and egg until well combined. Chill the dough in the refrigerator for at least 1 hour, up to 4 hours.
3. Step
On a generously floured surface, use a rolling pin to roll out the dough to ¼-inch thick. Use a snowflake cookie cutter to cut out cookies, then gently transfer to the prepared baking sheet, spacing 2 inches apart. Gather the dough scraps and re-roll to cut out more cookies up to 2 more times.
4. Step
Bake the cookies for 8–12 minutes, until just barely golden brown around the edges. Remove from the oven and let cool completely on the pans.
5. Step
To decorate, draw a snowflake pattern on the cookies with icing, then top with festive sprinkles.
