Follow directions on pastry package for standing, unfolding and flouring. Arrange one circle of pastry, floured side down on one-half of 10x15 inch jelly roll pan, gently stretching pastry into corners to line pan. Repeat with second circle of pastry on remaining half of jelly roll pan. Trim overlap in center of pan; use trimming to fill in around edges. Pinch pastry edges together firmly, patting and smoothing out seams. Trim pastry evenly,extending edge slightly above pan; flute edges. Refrigerate pastry 15 minutes. Line pastry with foil, fill with dried beans or rice. Bake in preheated 350 degree oven on lowest rack 15 minutes; remove beans and foil. Bake an additional 8-10 minutes; do not brown. Remove from oven, sprinkle Gruyere cheese over hot crust. Cover, store at room temperature up to 24 hours. Whisk together half and half, eggs, dill, Parmesan, onions, salt, mace and pepper. Refrigerate, covered.