You are but half an hour from a perfect tart crust—no kneading, no chilling, no rolling. All praise Paule Caillat, a Parisian cooking-school teacher who learned the technique from her husband's grandmother. It calls for heating butter and vegetable oil in a bowl in the oven, then adding flour, which froths exuberantly. Seconds later it's ready to be pressed into tins and baked. The golden, fragrant shell is perfect for filling with anything you like, but we keep it simple with pastry cream and berries so the miraculous crust can speak for itself.