Peel the wax from the cheeses and cut a 1-inch-thick slice off the top of each.
With a spoon, scoop out the center of the cheese leaving a boat-like shell about 1/2 inch thick.
Hollow the slice from the top in a similar manner to make a lid for the shell.
Place the lid and shell in a large pan or bowl, pour in enough cold water to cover them by at least 1 inch, and let them soak for 1 hour.
Grate enough of the scooped-out cheese to make 2 cups and set it aside.
Brown the meat for a short time.
Remove the cheese shells and lids from the water and invert them on paper towels to drain.
Preheat oven to 350°F.
With a pastry brush, spread the tablespoon of softened butter evenly over the bottom and sides of two round baking dishes at least 3 inches deep and just large enough to hold the cheese compactly.
(If the dish is too large or shallow, the cheese will collapse and spread when it is baked.) In a heavy 10-inch skillet melt the remaining 2 tablespoons of butter in the vegetable oil over moderate heat.
Drop in the onion and stirring frequently, cook for about 5 minutes, until the onions are soft and transparent but not brown.
Watch carefully for any sign of burning and adjust heat accordingly.
Add the tomato, pepper, salt, and a few grindings of black pepper, and still stirring, cook briskly until most of the liquid in the pan has evaporated and the mixture is thick enough to almost hold its shape in the spoon.
With a rubber spatula, transfer the entire contents of the skillet to a deep bowl.
Add the meat, grated cheese, bread crumbs, olives, gherkin, and raisins, and toss together gently but thoroughly.
Taste for seasoning and adjust, then stir in the beaten egg.
Spoon the meat mixture into each cheese shell, place the shells in the prepared dishes, and top them with the cheese lids.
Bake uncovered on the middle shelf of the oven for about 20 minutes or until the top is bubbly and delicately browned, and the meat tender.