Ingredients

• 1 cup Unbleached White All-Purpose Flour (136 g) or Gluten Free 1-to-1 Baking Flour
• ¼ cup Powdered Sugar (30 g)
• 1 Tbsp Lemon Zest (6 g)
• ¼ tsp Kosher Salt
• ½ cup Butter, cubed (112 g)

• 1 cup Granulated Sugar (240 g)
• ½ cup fresh squeezed Lemon Juice (from 3–4 lemons) (124 mL)
• 3 Tbsp Arrowroot Starch (27 g)
• 3 Egg Yolks (90 g)

• 3 Egg Whites (60 g)
• ¼ tsp Cream of Tartar
• ⅓ cup Granulated Sugar (80 g)
• ½ tsp Vanilla Extract

Instructions

1. Preheat oven to 350°F; butter an 8 x 8-inch baking pan and line with parchment paper.
2. Place flour, powdered sugar, lemon zest and salt in a food processor and pulse to incorporate. Add butter and process until the mixture is the texture of cornmeal.
3. Pour mixture into the prepared pan, spread evenly, and press firmly into the pan to form a crust. Bake at 350°F until the edges are just beginning to color, 20–25 minutes.
4. While the crust is baking, make the lemon layer. Place sugar, lemon juice, and arrowroot starch in a medium saucepan and bring to a simmer over medium heat, stirring to dissolve the sugar.
5. Place egg yolks in a medium bowl. Once lemon mixture begins to simmer, reduce heat to low. Ladle a few spoonfuls of hot lemon mixture into the egg yolks and whisk to loosen and incorporate.
6. Slowly stream the yolks into the lemon mixture, whisking continuously until the mixture thickens and easily coats the back of a spoon. Adjust the heat as needed to avoid the mixture becoming lumpy. Pour the lemon layer over the warm crust and smooth evenly. (If the lemon mixture is lumpy, strain through a fine mesh sieve.)
7. Chill in the refrigerator while the broiler heats (see next step) and the meringue is prepared.
8. Move the oven rack to the highest position and heat the broiler to low. Place egg whites and cream of tartar in a clean and dry mixing bowl. Whisk until very foamy then slowly stream in granulated sugar. Continue to whisk until medium-stiff peaks form, then fold in vanilla extract.
9. Layer meringue over the lemon layer, making swoops and swirls with a spatula. Place under the broiler and broil until the meringue begins to toast, 2–4 minutes.
10. Remove from oven and let cool completely (about 30 minutes) before portioning and serving. Store chilled for up to 4 days.