Ingredients

• 1 cup (2 sticks) unsalted butter, at room temperature
• 1/2 cup packed light brown sugar or muscovado sugar
• 1 2/3 cup all-purpose flour
• 1/3 cup cornstarch
• Pinch of salt

Instructions

1. 1. Position a rack in the center of the oven and preheat to 350 degrees. Lightly butter a 9- to 9 1/2 inch springform pan.
2. 2. Beat the butter in a medium bowl with an electric mixer set at high speed until smooth, about 1 minute. Add the sugar and beat until the mixture is light in color and texture, about 2 minutes. Using a wooden spoon, stir in the flour, cornstarch, and salt. Press the dough evenly into the pan. Using the tines of a fork, press around the perimeter of the dough. Prick the dough, reaching down to the bottom of the pan, into 10 equal wedges.
3. 3. Bake until lightly browned, about 30 minutes. Cool completely in the pan. Remove the sides of the pan. Cut the shortbread into wedges, following the perforations in the dough. (The shortbread can be stored in an airtight container for up to 5 day.)