8 ounces (2 sticks) unsalted butter, softened at room temp.
2/3 cup confectioners' sugar (measured then sifted)
2 large egg yolks (divided use: 1 for dough, 1 for coating)
pinch of salt
2 tsp vanilla extract
2-4 tsp finely grated lemon zest (to taste)
2 cups all purpose flour
approximately 1/2 cup granulated sugar (for coating)