Cook garlic and onion until wilted, about 3 minutes. Add eggplant and tomatoes and cook 5 minutes. Stir in tomato paste, oregano, tomato juice, stock and parsley. Bring to a boil and simmer partially covered 15 minutes. Taste for salt and pepper.
Sprinkle bread slices with cheese and toast or broil until melted and lightly browned.
Ladle soup into bowls and top with cheese toasts. Pour into large shallow, glass bowl. Allow to sit 30 minutes, turn eggplant again and let sit another 30 minutes. Meanwhile preheat grill. Place eggplant close to heat source and cook about 4 minutes or just until light char marks appear.