Adapted from: Erika's Kitchen
1/2 cup + 2 Tbsp powdered sugar
1/2 cup (1 stick) butter, melted
pinch of salt
1 cup granulated sugar
1/2 tsp baking powder
1/4 cup fresh lemon juice (about 6 small lemons)
1. Preheat the oven to 350 degrees. Spray a 9x9-inch pan with baking spray, then line the pan with aluminum foil (this will make it easier to remove the lemon bars in one piece so you can cut them properly on a cutting board). Spray the aluminum foil with baking spray as well.
2. In a bowl, mix together 1 cup of the flour, 1/2 cup of the powdered sugar, the melted butter, and the 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 the crust about 15 minutes or until it just starts to turn golden.
3. While the crust is baking, whisk together the remaining 2 Tbs flour, eggs, granulated sugar, baking powder and lemon juice.
4. Pull the crust out of the oven, pour over the lemon mixture, and return the pan to the oven for another 30 minutes, or until the center no longer jiggles when you shake the pan. Cool the lemon bars in the pan for half an hour, then refrigerate at least two hours before cutting. This will help you get nice, even edges.
5. Lift the foil with the bars out of the pan, this will make cutting them much easier. Cut with a large knife into 16 even squares. Dust the lemon bars with the remaining 2 Tbsp powdered sugar before serving.
Makes 16 squares.