Rich shortbread is easy to prepare and keeps for several days in an airtight container. Softened butter should be pliable but not easily spreadable. You can also use grated orange rind in place of lemon. A little bit of cornstarch ensures a short texture in the cookies.
2 dozen (serving size: 1 cookie)
1. Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, cornstarch, lemon rind, and salt in a small bowl; stir with a whisk.
2. Place sugar, butter, and oil in a medium bowl; mix with hands until combined. Add flour mixture, and mix with hands until combined; knead dough lightly 4 times or just until smooth. Wrap in plastic wrap. Refrigerate 30 minutes.
3. Preheat oven to 325°.
4. Place dough on a baking sheet coated with cooking spray; press dough into an 8 x 5–inch rectangle about 3/8-inch thick. Pierce entire surface liberally with a fork. Bake at 325° for 30 minutes or just until set and edges are golden. Cut shortbread into 24 pieces. Cool completely.