Prepare a puff paste. Roll it one and a half inches thick. Cut a circle six to six and a half inches in diameter, using as guide a pie-tin or cardboard, if a regular cutter is not at hand. Place it with care on a baking-tin, and cut a smaller circle around the top, one and a half inches from the edge, and two thirds through the paste. Paint over the top with yolk of egg, and bake it in a hot oven for thirty minutes. Do not open the oven door for the first fifteen minutes. When baked, lift off the inside circle. Cut out the uncooked paste, paint it over with white of egg, and place it again in the oven to brown. Keep the crust hot until ready to serve. Then fill with salpicon, and replace the cover, or small circle of paste.