MAKES 16 WEDGES
Use the collar of a springform pan to form the shortbread into an even round. Mold the shortbread with the collar in the closed position, then open the collar, but leave it in place. This allows the shortbread to expand slightly but keeps it from spreading too far. The extracted round of dough in step 2 is baked alongside the rest of the shortbread. The shortbread will keep for up to one week in an airtight container or cookie tin stored at room temperature. See the sidebar that follows the recipe.
|
½ |
cup (1½ ounces) old-fashioned rolled oats |
|
1½ |
cups (7½ ounces) all-purpose flour |
|
¼ |
cup cornstarch |
|
⅔ |
cup (2⅔ ounces) confectioners’ sugar |
|
½ |
teaspoon salt |
|
14 |
tablespoons unsalted butter, chilled and cut into ⅛-inch-thick slices |
1. Adjust oven rack to middle position and heat oven to 450 degrees. Pulse oats in spice grinder or blender until reduced to fine powder, about 10 pulses (you should have ¼ to ⅓ cup oat flour). Using stand mixer fitted with paddle, mix oat flour, all-purpose flour, cornstarch, sugar, and salt on low speed until combined, about 5 seconds. Add butter to dry ingredients and continue to mix until dough just forms and pulls away from sides of bowl, 5 to 10 minutes.
2. Place upside-down (grooved edge should be at top) collar of 9- or 9½-inch springform pan on parchment paper–lined baking sheet (do not use springform pan bottom). Press dough into collar in even ½-inch-thick layer, smoothing top of dough with back of spoon. Place 2-inch biscuit cutter in center of dough and cut out center. Place extracted round alongside springform collar on baking sheet and replace cutter in center of dough. Open springform collar, but leave it in place.
3. Bake shortbread for 5 minutes, then reduce oven temperature to 250 degrees. Continue to bake until edges turn pale golden, 10 to 15 minutes longer. Remove baking sheet from oven; turn oven off. Remove springform pan collar; use chef’s knife to score surface of shortbread into 16 even wedges, cutting halfway through shortbread. Using wooden skewer, poke about 10 holes in each wedge. Return shortbread to oven and prop door open with handle of wooden spoon, leaving 1-inch gap at top. Allow shortbread to dry in turned-off oven until pale golden in center (shortbread should be firm but giving to touch), about 1 hour.
4. Transfer sheet to wire rack; let shortbread cool to room temperature. Cut shortbread at scored marks to separate before serving.