For the crust:

1 1⁄4 cups (6 oz.) all-purpose flour, plus more for dusting
6 tbsp. (3 oz.) cold unsalted butter, cut into small cubes
1⁄2 tsp. kosher salt

For the filling:

1 packet powdered gelatin (2¼ tsp.)
4 large eggs, whites and yolks separated, at room temperature
3⁄4 cup (5½ oz.) sugar
1⁄2 cup fresh lemon juice
1 tbsp. finely grated lemon zest
1⁄4 tsp. kosher salt
1⁄2 cup heavy cream
1⁄4 tsp. pure vanilla extract