Vanilla-Bean Sugar Cookies
In a stand mixer fitted with paddle attachment, beat butter with granulated sugar and salt on medium speed until light and fluffy, about 2 minutes. Add egg yolk and vanilla; beat to combine. Add flour and beat until a soft dough forms, about 30 seconds. Divide in half; place each half between two sheets of floured parchment and roll out to 1/4-inch thickness. Refrigerate 15 minutes.Advertisement
Preheat oven to 325°F. Using a cookie cutter, cut dough into 1 1/4-inch rounds. Gather scraps and reroll; refrigerate 15 minutes and cut more rounds. Refrigerate rounds 20 minutes. Brush edges of cookies with egg white; roll in sanding sugar to coat. Arrange on parchment-lined baking sheets, 1 inch apart. (If dough is softening, return to refrigerator 10 minutes.)
Bake, rotating halfway through, until cookies are just golden on bottoms, 15 to 18 minutes. Let cool completely on pans on wire racks. Cookies can be stored in an airtight container at room temperature up to 1 week.
To slice-and-bake these cookies, roll the dough into a 1 1/4-inch-diameter log at the end of step 1 and refrigerate for an hour. Brush with egg white, roll in sanding sugars, and cut into 1/4-inch slices, then place on sheets and bake per step 2.