Preheat oven to 350°F and butter (or spray with cooking oil) an 8”x8” square baking pan, line the pan with a long strip of parchment paper and let the excess hang over the side.
In a small bowl, add flour and salt, and thoroughly combine with a whisk.
In the stand mixer bowl, cream butter, sugar and vanilla extract with a paddle attachment until light in color.
Add the flour mixture and mix on low until a dough ball forms.
Dump the dough into the previously prepared baking pan and press it into an even layer.
Bake the crust for 20 minutes until lightly brown.
Let cool on a wire rack while you prepare the lemon filling. Leave the oven on.
In a medium mixing bowl with a spout (or a large measuring cup), add lemon zest and sugar and mix with a whisk to release lemon oil. The sugar will turn light yellow.
Add eggs, lemon juice, salt and flour and mix until thoroughly combined.
Pour the mixture over the crust and bake for 25 - 30 minutes until the filling is set.
Let cool completely on a wire rack before cutting.
Lift the lemon bar out of the baking pan using the parchment paper excess. Cut into 4 squares, then cut each square into 4 triangles. Dust with powder sugar.
