Line unpricked pastry shell with a double thickness of heavy-duty foil. Bake at 450° for 5 minutes. Remove foil. Bake 5 minutes longer. Cool completely.
Sprinkle bacon over the crust. Top with tomato and cheese. In a large bowl, beat the egg yolks, sour cream, flour and salt until smooth. In another large bowl, beat egg whites until stiff. Fold into sour cream mixture; spread over cheese. Sprinkle with paprika.
Bake at 350° until a knife inserted in the centre comes out clean, about 45 minutes. Let stand 5-10 minutes before cutting.