01 -
Whisk the flour, baking soda, and salt in a medium bowl.
02 -
Mix the vanilla and egg with a fork in a small bowl.
03 -
Beat the butter, granulated sugar, and confectioners' sugar in the bowl of a stand mixer on low speed until the butter absorbs the sugars, about 30 seconds. Increase to medium speed and beat until creamy, scraping the bowl halfway, about 1 minute.
04 -
Reduce mixer speed to low and slowly add the egg mixture, beating until fully combined.
05 -
Add the flour mixture in two additions, a heaping cup at a time, stopping to scrape the bowl and beaters. Once combined, add the edible confetti stars and mix on medium speed until the dough is smooth, about 2 minutes.
06 -
Divide the dough into two equal pieces (about 11 ounces each). Shape each into a 6-inch square, wrap in plastic wrap, and refrigerate for at least 3 hours or overnight.
07 -
Preheat oven to 350°F (175°C). Line two baking sheets with parchment paper. Roll out the dough to 1/4 inch thickness on a floured surface. Use 3 1/2-inch and 1 1/2-inch star-shaped cookie cutters to cut the dough. Transfer the stars to baking sheets and sprinkle with additional confetti stars.
08 -
Freeze the cookie sheets for about 10 minutes to firm the dough.
09 -
Bake the cookies, rotating the baking sheets halfway through, for 18-20 minutes until light golden around the edges. Cool on the baking sheets for 30 minutes.