Thick, tangy-sweet lemon curd baked over a buttery shortbread crust, yielding a creamy, bright bite with a delicate dusting of confectioners’ sugar.
Preheat the oven to 325°F (163°C). Line the bottom and sides of a 9×13-inch glass baking pan with parchment paper, leaving an overhang for easy lifting.
Make the crust: In a medium bowl, mix the melted butter, granulated sugar, vanilla extract, and salt. Add the flour and stir until a thick dough forms.
Press the dough firmly and evenly into the prepared pan. Bake for 20–22 minutes, or until the edges are lightly browned. Remove from the oven.
Using a fork, poke holes all over the top of the warm crust (do not poke all the way through). Set aside.
Make the filling: In a large bowl, sift together the granulated sugar and flour. Whisk in the eggs, then whisk in the lemon juice until completely combined.
Pour the filling over the warm crust. Bake for 22–26 minutes, or until the center is relatively set and no longer jiggles when gently tapped.
Cool completely at room temperature (about 2 hours), then refrigerate 1–2 hours until chilled.
Lift the slab out using the parchment overhang. Dust with confectioners’ sugar, slice into squares (wiping the knife clean between cuts), and serve.
Storage: Cover and refrigerate leftovers for up to 1 week.
Freezing: Cut (without sugar dusting), freeze on a sheet for 1 hour, then wrap bars individually and freeze up to 3–4 months. Thaw in the refrigerator and dust before serving.