Line 13 x 9-inch baking pan with foil, and coat with cooking spray.
Preheat oven to 350° F.
To make crust: blend butter, sugar, and salt in large bowl until smooth. Stir in flour. Scrape into pan, pressing level. Bake for 20 minutes or until golden.
To make filling: beat sugar, flour, eggs, and lemon juice in bowl until smooth. Pour over baked crust. Place back in 350° F oven for 25 minutes, until no imprint remains when lightly touched in center. Cool on rack.
Remove from pan, and cut into squares. Dust with powdered sugar.
Lemon bars may be stored in an airtight container in the refrigerator for up to four days