Preheat your oven to 175°C (350°F). Line your baking dish with parchment paper, leaving an overhang for easy removal.
In a mixing bowl, combine 1 1/2 cups of all-purpose flour, 1/4 cup of granulated sugar, and a pinch of salt. Add the cold, cubed butter and use your fingers or a pastry cutter to work it into the flour until the mixture resembles coarse crumbs.
Press this crumbly mixture evenly into the bottom of the prepared dish. Bake for 20-25 minutes, until the crust turns golden and fragrant.
While the crust bakes, zest two lemons using a microplane, then juice them until you have about 1/2 cup of lemon juice. In a separate bowl, whisk together the eggs, 1 1/2 cups of sugar, lemon zest, and lemon juice until smooth and bright.
Sprinkle the 1/4 cup of flour into the lemon mixture and whisk again until fully combined and silky.
Pour the lemon filling over the hot crust straight from the oven. Return the dish to the oven and bake for an additional 20-25 minutes, until the filling is set but still slightly jiggly in the center and the edges are lightly browned.
Remove from the oven and allow to cool completely in the dish. Once cooled, chill in the refrigerator for at least 2 hours to fully set.
Lift the lemon bars out using the parchment overhang and cut into neat squares with a sharp knife. Dust with powdered sugar if desired and serve chilled or at room temperature.
