Preheat your oven to 350°F (175°C) and lightly grease an 8" x 8" baking pan.

In a mixing bowl, combine softened butter, all-purpose flour, and powdered sugar. Blend until it resembles coarse crumbs, then press into the bottom of the pan.

Chill the crust in the refrigerator for 10-15 minutes, then bake for 12-15 minutes until lightly golden.

Prepare the lemon filling by whisking together fresh lemon juice, lemon zest, eggs, granulated sugar, and sifted flour until smooth.

Pour the lemon filling over the cooled crust and bake for 25-30 minutes until set.

Let the bars cool completely on a wire rack, then refrigerate for at least 1 hour.

Dust with powdered sugar before serving and cut into squares or rectangles.