Recipe from MacrinaBakery.com
8 ounces (2 sticks) unsalted butter, at room temperature
1 cups powdered sugar, sifted
1 egg, separated
1 tsp pure vanilla extract
2 ¼ cups unbleached all-purpose flour
1 cup finely chopped walnuts
Sugar crystals in your favorite colors
Tips on making these cookies:
Lay roll out against a measuring device to cut even 1/2 inch slices. Score the roll with a knife, then cut full slices.
Cut a stencil out of parchment paper if you don’t have a stencil to work with.
Instructional video from Macrina Bakery (start at 6:13 for Swedish Overnights)