- Unsalted butter (for pan)
- Gluten-Free Multi-Purpose Sweet Pastry Dough (you'll need one disc; freeze remaining disc for another use)
- 4 large eggs
- 1 1/2 cups granulated sugar
- 1/4 cup all-purpose gluten-free flour
- 1 tablespoon finely grated lemon zest (from about 1 1/2 lemons)
- 1/2 cup fresh lemon juice (from about 4 lemons)
- 1/4 teaspoon kosher salt
- Powdered sugar (for dusting)
- An 8x8x2″ baking pan
- Position rack in center of oven; preheat to 350°F. Butter baking pan, then line with 2 layers of parchment, leaving a 2″ overhang on all sides. Butter parchment.
- Press dough into bottom and about 3/4″ up sides of prepared pan. Poke all over with a fork and chill at least 30 minutes.
- Bake crust until golden brown, about 25 minutes. Transfer to a wire rack and let cool.
- Meanwhile, whisk eggs, granulated sugar, flour, lemon zest, lemon juice, and salt in a medium bowl. Pour filling into crust and bake bar until set and slightly golden brown at the edges, about 25 minutes. Transfer pan to a wire rack and let cool completely, then chill at least 2 hours or up to overnight.
- Loosen edges with an offset spatula or butter knife, then use parchment overhang to remove bar from pan. Transfer bar on parchment to a cutting board and cut into 4 pieces lengthwise and 3 pieces crosswise to make 12 rectangular bars. Dust bars with powdered sugar.
- Bars can be made 2 days ahead. Keep chilled in baking pan.