Cream butter, sugar, and vanilla together until smooth.
Mix in flour.
Mix in chocolate chips by hand.
Put dough on parchment paper, and shape into a rectangle that is 2” tall and 4” wide. Wrap in parchment paper and chill in the refrigerator for 2 hours.
Preheat oven to 325° f.
Remove chilled dough from the refrigerator and unwrap. Slice dough into ¼ - ½” thick slices. Place sliced cookies onto a parchment lined baking sheet about 2” apart.
Bake for 18-22 min. Shortbread should be barely golden on the bottom. Let cool on pan for 10 minutes. Finish cooling on cooling rack.