• Preheat your oven to 350°F (175°C) and line a 9x13-inch pan with parchment paper, leaving overhang for easy removal. Do not grease the pan.

If Using a Food Processor

• In the food processor, combine the sugar and lemon zest. Pulse for a few seconds to infuse the sugar with lemon flavor.
• Add the butter and pulse until the mixture is creamy and well combined.
• Add the vanilla extract, lemon extract (if using), egg, and yolk. Pulse until just incorporated.
• Add the gluten-free flour and salt. Pulse until the dough comes together and forms a cohesive mixture.
• Press the dough firmly and evenly into the pan and refrigerate for 20 -30 minutes.
• Prick the dough all over with a fork. Bake for 20-25 minutes or until lightly golden. Allow to cool slightly while preparing the filling.

  ***To prevent your crust from lifting and the filling from going under it, make sure the crust is firmly pressed to all edges - if desired you can push the crust slightly up the sides. You may also choose to blind bake the crust covered with parchment and pie weights to prevent it from pulling away from the sides.

If Using a Stand Mixer

• Preheat the oven to 350°F (175°C) and prepare the pan as described above.
• In a large bowl, combine the sugar and lemon zest. Rub them together with your fingers to release the oils.
• Add the softened butter and beat with a stand mixer or hand mixer until light and fluffy.
• Mix in the vanilla extract, lemon extract (if using), egg, and yolk, beating until combined.
• Gradually add the gluten-free flour and salt, mixing until a smooth dough forms.
• Press the dough into the pan evenly and refrigerate for 20 -30 minutes.
• Prick the dough all over with a fork. Bake for 20-25 minutes, until lightly golden brown, then set aside to cool slightly.

  ***To prevent your crust from lifting and the filling from going under it, make sure the crust is firmly pressed to all edges - if desired you can push the crust slightly up the sides. You may also choose to blind bake the crust covered with parchment and pie weights to prevent it from pulling away from the sides.

For The Filling

• In a large bowl, whisk the eggs until well combined.
• Sift in the gluten-free flour and sugar, whisk until fully incorporated.
• Add the lemon juice and lemon zest. Whisk until the mixture is smooth.
• Very slowly pour the filling over the slightly cooled crust. The crust will be fairly thin and you don't want it to get under the crust as this will make the crust float.
• Bake for 25-30 minutes, or until the filling is set and no longer jiggles.
• Remove from the oven and let cool completely in the pan.
• Chill in the refrigerator for at least 2 hours (preferably overnight) .
• Dust with powdered sugar before serving for a classic finish.
• Slice into squares and enjoy!
• Store leftovers in an airtight container in the refrigerator for up to 4 days.