Preheat oven to 350 degrees F. Line the bottom of an 8'' pan with parchment paper, or grease with cooking spray and set aside.

Shortbread Crust: In a mixing bowl or the bowl of a stand mixer, cream together the butter and powdered sugar. Add the flour and salt and mix on low speed, just until combined.

Bake Crust: Press the dough evenly into the bottom of the prepared dish. Bake for 10 minutes. Remove from oven and set aside.

Lemon filling: Mix lemon zest and sugar in a mixing bowl. Add the lemon juice, flour, baking powder, and eggs. Mix until well combined and the sugar is dissolved. Pour mixture over the baked crust.

Bake lemon bars at 350 degrees F for 35-40 more minutes, or until the filling has set. Remove from oven and allow to cool completely.

Dust with powdered sugar before cutting and serving. Store lemon bars in the refrigerator.