This recipe makes two logs of dough. The logs can be refrigerated for up to four days or frozen for up to three months (thaw before slicing and baking). To make two flavors with one recipe, divide the dough in half in step 1 before adding mix-ins (and use half the amounts given).
For the Shortbread
- 1 cup (2 sticks) unsalted butter, room temperature
- 1 cup confectioners' sugar
- 1 teaspoon vanilla extract
- 1/2 teaspoon salt
- 2 cups all-purpose flour (spooned and leveled), plus more for rolling
Flavor Variations (optional mix-ins and coatings)
- Mix in grated zest of 2 oranges and 1/2 cup dried cranberries
- Mix in grated zest of 2 lemons; coat with 1/4 cup poppy seeds
- Mix in grated zest of 2 limes; coat with 1/4 cup cornmeal
- Mix in 1/2 cup chopped dried apricots; coat with 1/2 cup finely chopped pistachios
- Mix in 1/2 cup mini chocolate or peanut-butter chips
- Mix in 1/4 cup finely chopped candied ginger; coat with 1/4 cup sesame seeds
With an electric mixer, beat butter, sugar, vanilla, and salt until smooth. With mixer on low speed, add flour, mixing just until a dough forms. Stir in desired mix-ins.
Divide dough in half; place each half on a piece of floured waxed or parchment paper. With floured hands, gently roll each into a 1 1/2-inch-diameter log. Dividing evenly, sprinkle logs with desired coating if using, rolling log (to help coating adhere) and pressing in gently. Wrap logs tightly in the paper, and refrigerate until firm, 1 to 1 1/2 hours. (To store longer, wrap log and paper tightly with plastic wrap.)
Preheat oven to 350 degrees. Unwrap logs; with a serrated knife, slice dough 3/8 inch thick (if dough crumbles, leave at room temperature 5 to 10 minutes). Arrange slices, about 1 inch apart, on baking sheets.
Bake until lightly golden around the edges, 15 to 20 minutes. Cool on baking sheets 1 to 2 minutes; transfer to a wire rack to cool completely.