Ingredients
1 1/2 cups (3 sticks) unsalted butter, room temperature, plus more for pan
2 1/2 cups unbleached all-purpose flour
1/2 teaspoon kosher salt
3/4 teaspoon white peppercorns, coarsely ground
3/4 teaspoon black peppercorns, coarsely ground
3/4 teaspoon pink peppercorns, coarsely ground
3/4 teaspoon green peppercorns, coarsely ground
3/4 cup confectioners' sugar
2 tablespoons granulated sugar
Preparation
Preheat oven to 300 degrees, with rack in center. Lightly butter four 4 1/2-inch springform pans (or one 10-inch springform pan).
Whisk to combine flour, salt, and 1/2 teaspoon of each ground peppercorn. In a separate bowl, beat butter and confectioners’ sugar with an electric mixer on medium-high speed until pale and fluffy, 3 to 4 minutes, scraping down side of bowl. Reduce speed to low. Gradually add flour mixture; mix just until combined.
Divide dough evenly among prepared pans, and smooth tops using an offset spatula (or press into 10-inch pan, if using, and lightly score into 8 wedges). Bake, rotating pans halfway through, until golden brown, about 40 minutes (or 80 minutes for 10-inch).
Transfer pans to a wire rack. Immediately sprinkle with granulated sugar and remaining ground pepper, dividing evenly. Remove pans; let cool completely on rack. (If using 10-inch pan, cool slightly before cutting into wedges.) Shortbread can be stored in an airtight container at room temperature up to 2 weeks.
