Lemon-Glazed Shortbread Bars

Step 1: Preheat oven to 300 degrees F.

Step 2: Line a 13x9x2-inch baking pan with heavy foil, extending foil 2 inches over each end of the pan. Lightly grease foil; set aside.

Step 3: In a medium bowl, stir together flour and cornstarch. In a small bowl, combine powdered sugar and lemon peel. Using your fingers or pressing against side of bowl with a wooden spoon, work lemon peel into powdered sugar until sugar is yellow and very fragrant; Set aside.

Step 4: In a large bowl, combine butter, lemon juice, salt, and vanilla; beat with an electric mixer on medium speed until combined. Gradually beat in sugar mixture. Beat in as much of the flour mixture as you can with the mixer. Stir in any remaining flour mixture. Continue beating or stirring until dough comes together. Gather dough into a ball.

Step 5: Press dough evenly into the prepared pan.

Step 6: Bake on center rack of the oven 40 minutes.

Step 7: Meanwhile prepare the glaze; In a medium bowl, combine powdered sugar, finely shredded lemon peel, lemon juice, light-color corn syrup, and vanilla. Whisk until smooth.

Step 8: Remove the bars from oven. Immediately dollop glaze over top, then gently spread to evenly distribute the glaze. Let cool completely.

Step 9: Using the edges of the foil, lift the uncut bars out of the pan. Cut into 24 squares. Cut each square in half, diagonally.