Preheat oven to 350°F. Spray a 9x13-inch cake pan with nonstick spray and line with parchment paper. Set aside.
In a large bowl, whisk together the flour, powdered sugar, and salt. Add the melted butter and stir until a soft dough forms and there are no more patches of dry ingredients.
2 cups all-purpose flour, ½ cup powdered sugar, ¼ teaspoon fine sea salt, 1 cup unsalted butter
Evenly press the crust mixture into the bottom of the prepared pan. Bake for 18-20 minutes, or until the edges of the crust are lightly golden.
While the crust bakes, make the filling. In a large bowl, whisk together the eggs, sugar, and baking powder until well combined. Add the lemon juice and zest and whisk until the filling is smooth and well combined. Set aside until the crust is done baking. The top of the filling will get a bit foamy while it sits—this is ok.
When the crust is done baking, pour the filling over the hot crust. Return the pan to the oven and continue baking for another 20-25 minutes, or until the top is golden and crackly and the center barely jiggles when you lightly shake the pan.
Allow the lemon bars to cool completely. Transfer the pan to the fridge to chill for at least 1 hour before serving.
To serve, remove the bars from the pan, dust the tops generously with powdered sugar, and cut into squares.
Powdered sugar
Notes
Ingredients
You'll need about 2 large or 3 small lemons to get 6 tablespoons of juice.
Storage
Store in an airtight container in the refrigerator for up to 3 days.