Using a stand mixer or hand mixer, cream together butter & sugar.
Add egg & vanilla. Mix to combine.
Fold in dry ingredients by hand using a spatula until just combined.
Refrigerate about 30 mins, then press into the bottom of a large loaf pan (10x5) (an 8x8 pan will also work) lined with parchment. Bake at 315ºF for 15 mins.
Remove crust from the oven and prepare filling while it cools. Turn oven temp up to 350ºF