1. Preheat the oven to 375°. Scrub the outside of the pumpkin under cold running water with a stiff brush. With a large, sharp knife, cut down into the top of the pumpkin to create a lid 6 or 7 inches in diameter. Leave the stem intact as a handle. Lift out the lid and, with a large metal spoon, scrape the seeds and stringy fibers from the lid and from the pumpkin shell.
2. Brush the inside of the pumpkin with the soft butter and sprinkle the cup of sugar into the opening. Tip the pumpkin from side to side to make the sugar adhere to the butter. Then turn the pumpkin over and gently shake out the excess sugar. Put the lid back in place.
3. Place the pumpkin in a large shallow roasting pan and bake in the oven for 45 minutes, or until tender but somewhat resistant when pierced with the tip of a small, sharp knife. The pumpkin shell should remain firm enough to hold the filling without danger of collapsing.
4. Meanwhile, heat the oil over moderate heat in a heavy 6- to 8-quart casserole until a light haze forms above it. Add the cubes of meat and brown them on all sides, turning them frequently with a large spoon. Regulate the heat so the meat browns quickly without burning. Then with a slotted spoon, transfer the meat to a platter.
5. To the fat remaining in the pan, add the onions, green pepper and garlic, and cook over moderate heat, stirring constantly, for about 5 minutes, or until the vegetables are soft but not brown.
6. Pour in the fresh beef stock or canned beef stock and water and bring to a boil over high heat, meanwhile scraping in any brown bits clinging to the bottom and sides of the pan.
7. Return the meat and any of its accumulated juices to the pan and stir in the tomatoes, oregano, bay leaf, salt and a few grindings of black pepper. Cover the pan, reduce the heat to low, and simmer undisturbed for 15 minutes.
8. Then add the sweet potatoes and white potatoes, cover the pan and cook for 15 minutes; add the zucchini slices, cover the pan again and cook for 10 minutes. Finally add the corn rounds and peach halves and cook, still covered, for 5 minutes longer.
9. Pour the entire contents of the pan carefully into the baked pumpkin, cover the pumpkin with its lid again, and bake for another 15 minutes in a 375° oven.
10. To serve, place the pumpkin on a large serving platter and, at the table, ladle the "carbonada" from the pumpkin onto heated, individual serving plates.
