Preparation Steps

• In a large mixing bowl, whisk together flour, baking powder, baking soda, and salt.
• In a separate large mixing bowl, using an electric hand mixer, blend together granulated sugar, butter, and lemon zest until combined. Increase speed to high and whip for about 1 minute until slightly pale and fluffy.
• Mix in the egg and egg yolk, then blend in 1.5 Tbsp lemon juice and the vanilla extract. The mixture may look a little separated due to acidity; this is okay. If desired, add a little natural yellow food coloring for a more yellow cookie.
• Add the flour mixture to the butter mixture and mix on low speed until combined. Scrape down the bowl and fold the dough with a spatula a few times to ensure it's evenly combined. Spread the dough out evenly.
• Chill the dough in the refrigerator for 45 to 60 minutes, or until it's not too sticky to work with. Chilling will also help the cookies spread less.
• Preheat the oven to 350°F (175°C) during the last 10 minutes of chilling the cookies.
• Line rimmed 18 by 13-inch baking sheets with parchment paper. Scoop dough about 1.5 Tbsp each (approximately 28g) and roll into a ball (they should be about the size of a golf ball). Transfer 12 cookie dough balls to the prepared baking sheet, spaced evenly apart. Keep the remaining dough chilled.
• Bake in the preheated oven until slightly under-baked in the center, about 9 minutes. Let cool on the pan for 5 minutes, then transfer to a wire rack to cool completely. Repeat baking with the remaining cookie dough.
• Once the cookies have cooled, mix together the powdered sugar with 2.5 Tbsp lemon juice. The glaze should have a medium, creamy thickness, drippy but not runny. Either spoon the glaze over the cookies and spread into a circle, or pipe the glaze from a small resealable bag with the corner cut.
• Let the glaze set before storing the cookies.