Trim any excess fat from beef and cook with onion and garlic in oil until meat is browned. Add tomatoes, green pepper, 1 tablespoon salt, half teaspoon pepper, sugar, apricots, white potatoes, sweet potatoes and broth. Cover and simmer 1 hour.
Meanwhile, cut top off pumpkin and discard. Scoop out seeds and stringy membrane. Brush inside of pumpkin with butter and sprinkle lightly with salt and pepper. Stir sherry and corn into stew and spoon into pumpkin shell. Place shell in shallow pan and bake at 160ºC or 1 hour, or until pumpkin meat is tender. Place pumpkin in large bowl and ladle out stew, scooping out some of pumpkin with each stew serving.