In Sweden, these shortbread cookies are traditionally cut into star shapes and garnished with pearl sugar, which can be found at specialty baking stores and online sources.
- 16 tbsp. unsalted butter, at room temperature
- 1 cup superfine sugar
- 2 eggs, separated
- 2 tsp. vanilla extract
- 4 cups flour
- 1 tsp. kosher salt
- Pearl sugar, for garnish
Combine butter and superfine sugar in a large bowl and beat, using a handheld mixer set to medium speed, until mixture is pale and fluffy, 1-2 minutes. Add egg yolks and vanilla and beat until smooth. Add flour and salt and beat until just combined. Transfer dough to a work surface and shape into a flat disk; wrap in plastic wrap and refrigerate for 1 hour.
Heat oven to 350°. Transfer dough to a floured work surface and, using a rolling pin, roll dough to a 1⁄8" thickness. Using a 2"-wide star-shaped cookie cutter, cut out cookies and place them 2" apart on baking sheets lined with parchment paper. In a small bowl, whisk egg whites until frothy. Using a pastry brush, brush egg whites evenly over cookies; sprinkle cookies with pearl sugar. Bake cookies, 1 sheet at a time, until just set, about 10 minutes. Transfer to a wire rack to let cool completely.