Shortbread Crust
Preheat the oven to 350 degrees.
Line an 8-inch by 8-inch baking dish with parchment paper. Leave a little parchment above the top of the dish to use as handles when lifting the squares out.
In a medium to large mixing bowl, stir together the flour, sugar, and salt.
Add the chilled butter. Use the pastry cutter (or a fork) and cut the butter into the flour mixture. Continue doing this until combined, and the butter is no bigger than the size of a pea.
Add the vanilla extract and continue cutting in until combined.
Push the shortbread crust into the bottom of the prepared pan.
Bake the crust for 10 minutes. Remove from the oven but leave the oven on.
In a medium mixing bowl, whisk together the brown sugar, whipping cream, eggs, melted butter, cornstarch, vanilla extract, and salt until smooth.
Pour the mixture over the warm crust and bake for 25 minutes. The outside edges will be crispy, while the middle will still be jiggly.
Cool completely before placing in the fridge to chill until set, 2-3 hours.
Once set, remove from the pan and cut into 16 equal squares.