Preheat your oven to 350 F (180 C).
Spray an 8 x 8 baking pan with non-stick cooking spray. Line the bottom of the pan with parchment paper, leaving the paper overhanging on both sides. Spray the paper with non-stick spray.
For the crust, get out your electric mixer. You can also do this by hand, it will just take a bit longer. Add the butter, sugar and salt to the bowl and mix on medium until light, fluffy, and pale yellow. This will take 3 – 5minutes. Add the vanilla and mix until combined. Add the flour, and mix on low until the flour is incorporated.
Press the dough into the bottom of the prepared pan and up the sides a bit. Prick the dough all over with a fork.
Bake for 15 minutes until the crust is a light golden colour.