Roasted Tomatoes Stuffed with Ratatouille

Ingredients

• 4 l large, ripe tomatoes
• Salt
• 1 medium red onion, cut crosswise into 10mm slices
• 1 medium red capsicum, stem and seeds removed, cut into flat pieces
• 1 medium zucchini, cut lengthwise in 10mm slices
• Extra-virgin olive oil
• Freshly ground black pepper
• ½ cup cup grated mozzarella cheese
• 1 tbsp tablespoon finely chopped fresh basil
• 1 tsp teaspoon balsamic vinegar