- 2 sticks (1/2 pound) unsalted butter, softened
- 8 ounces cream cheese
- 1 cup sugar
- 2 large egg yolks
- 1/2 teaspoon vanilla extract
- 1/4 teaspoon salt
- 1 3/4 cups all-purpose flour, plus more for rolling
- 1 large egg
- 1 tablespoon milk
- Colored sanding sugar
- In electric mixer, beat butter, cream cheese, and sugar at high speed until fluffy, about 5 minutes. Add egg yolks, vanilla, and salt and beat at medium speed until blended. Add flour and mix at low speed until just combined. Divide dough into thirds, form into 3 disks, and wrap in plastic wrap or waxed paper. Chill until firm, at least 1 hour or up to 2 days.
- Arrange racks in upper and lower thirds of oven and preheat to 375°F. Line 2 heavy large baking sheets with parchment paper. Beat together whole egg and milk to create egg glaze.
- Remove 1 dough disk from refrigerator. On well floured work surface, roll out dough to 1/8- to 1/16-inch thickness, dusting with more flour as necessary. Using 3- to 4-inch star cookie cutters, cut out cookies; transfer with spatula to baking sheets. Gather and reroll scraps and cut out additional cookies. Brush lightly with egg wash and sprinkle with sanding sugar.
- Bake cookies until golden and somewhat firm to touch, about 10 minutes. Cool on pans 2 minutes, then transfer to racks and cool completely. Repeat with remaining dough.