Preheat your oven to 350°F (175°C). Grease and flour the 9x13-inch baking dish or line it with parchment paper for easy removal.

In a mixing bowl, combine the softened butter and granulated sugar for the crust. Beat until the mixture is smooth and creamy.

Add the flour and salt to the butter mixture. Mix until just combined, forming a dough.

Press the crust mixture evenly into the bottom of the prepared baking dish. Bake in the preheated oven for 15 minutes or until lightly golden.

While the crust is baking, prepare the lemon filling. In a separate bowl, whisk together granulated sugar and flour until combined.

Add the eggs, lemon juice, and lemon zest to the sugar mixture. Whisk until smooth and well incorporated.

Once the crust is done, remove it from the oven and pour the lemon filling over the hot crust.

Return the baking dish to the oven and bake for an additional 20-25 minutes, or until the filling has set and does not jiggle when shaken.

Remove from the oven and allow the lemon bars to cool in the pan at room temperature. Once cooled, refrigerate for at least 2 hours to firm up.

Once chilled, cut into squares or bars and dust with powdered sugar, if desired. Serve chilled or at room temperature.