In a small bowl, combine the ground almonds with the ham, mushrooms, hardboiled eggs, sage, salt, and pepper. Add the egg and mix together well. Butterfly the loin by making a deep, even cut all along one side that reaches just to the center of the eye of the meat (or ask the butcher to do this as well). Open out the meat like a book and press the stuffing into this opening, then mold the meat around it and tie the roast at 1 inch intervals to keep the stuffing inside.
In a large cast-iron and enamel casserole heat the olive oil over medium heat. saute the loin, turning with heavy kitchen tongs and a wooden spoon to brown all sides evenly. Transfer the loin to a plate and add the reserved pork bones to the pan. Brown the bones in the fat until they are nice and golden. Set the bones aside, and pour off and discard the fat from the casserole. Pour in the brandy and deglaze the pan, stirring and scraping the bottom and sides to release all the flavorful bits. Add the veal stock, return the bones to the casserole, and bring the liquid to a simmer. Add the loin and, when the liquid returns to a simmer, reduce the heat, cover, and cook for 1 hour regulating the heat so that the liquid keeps simmering gently. Turn the loin over halfway through the cooking time. When cooked through, transfer the loin to a cutting board and cover loosely with aluminum foil. Remove and discard the bones from the sauce and, over high heat, reduce it by about 1/3. Stir in the lemon juice and then whisk in the cold butter, whisking just until the sauce is smooth, slightly thickened, and emulsified. Taste for seasoning and strain the sauce, if desired. Remove the strings, slice the roast and pass the sauce separately.
To toast almonds, preheat the oven to 350/. Spread the almonds on a cookie sheet and toast in the oven until golden, about 15 minutes. Set aside to cool. Ask the butcher to bone the loin, starting with a 5 to 6 pound pork loin, and leaving a little fat around it. Have the butcher cut the bones into about 16 pieces and reserve them.
Copyright 1997, M.S. Milliken & S. Feniger, all rights reserved