Preheat the oven to 350°F. Prepare a 9x9-inch pan with baking spray, then line the pan with parchment paper (this will make it easier to remove the lemon bars in one piece so you can cut them properly on a cutting board).
In a medium bowl, combine 1 cup flour, 1/2 cup powdered sugar, butter, and salt with a fork until a crumbly dough forms. Press the dough into the prepared pan so it covers the bottom and goes about 1/2 inch up the sides. Bake about 10 minutes or until it is a light golden brown.
While the crust is baking, whisk together the remaining 2 tablespoons flour, eggs, sugar, lemon juice and fine lemon zest.
Remove crust from oven, pour the lemon mixture over the crust.
Bake 20-25 minutes, or until the center is set (doesn’t jiggle when you shake the pan). Allow lemon bars to cool for 30 minutes in pan. Using parchment, remove lemon bars and set on cutting board. Allow to cool completely or refrigerate until completely cooled.
Cut into 16 squares. Sprinkle the remaining powdered sugar over the cooled lemon bars before serving.