1.Heat oil in a large saucepan over medium heat; cook onion, stirring, 5 minutes or until soft. Add eggplant, capsicum and garlic; cook, covered, over low heat, 20 minutes or until soft.
2.Add zucchini, tomatoes and stock; simmer, covered, 10 minutes or until zucchini is tender. Season to taste.
3.Meanwhile, make pistou. Blend or process garlic, olive oil and basil until almost smooth; season to taste. Transfer to a small bowl; cover tightly with plastic wrap.
4.Preheat grill. Split bread lengthways, then in half crossways. Spread with 2 tablespoons of the pistou then ricotta; sprinkle with parmesan. Place on an oven tray under the grill until browned lightly.
5.Ladle soup into serving bowls; top with remaining pistou. Serve with bread.