Cookie crust is the sweetest tart-shell dough of all, and is flavored with vanilla.
In the bowl of an electric mixer fitted with the paddle attachment, cream the butter and sugar until light and fluffy, 3 to 4 minutes. Add vanilla and egg yolks, one at a time, beating well after each addition. Add flour and salt; beat until just coming together but still crumbly.
Divide dough in half. Use immediately, or wrap each half in plastic wrap and refrigerate until ready to use.