Preheat the oven to 350°F. Line a 9x13-inch baking pan with parchment paper, leaving some overhang.
Whisk together the flour, powdered sugar, and salt. Add the melted butter and stir until a soft, crumbly dough forms. Press evenly into the prepared pan.
Bake for 18–20 minutes, until the edges are lightly golden and the center is set.
While the crust bakes, whisk the eggs and granulated sugar until smooth. Whisk in the flour, lemon zest, lemon juice, and salt until fully combined.
Pour the lemon filling over the hot crust immediately after it comes out of the oven.
Return the pan to the oven and bake for 20–25 minutes, until the edges are set and the center has only a slight jiggle. Cool completely on a wire rack.
Chill for at least 1 hour. Lift the bars from the pan using the parchment, dust with powdered sugar, and cut into 24 bars.