Provencal Ratatouille

Name: Provencal Ratatouille
Ingredients: 1 kg fresh tomatoes (or 600g tinned tomatoes); 200ml olive oil; 1 large onion (200g), peeled and finely diced; 6 garlic cloves, peeled and lightly crushed with the flat side of a heavy knife; a couple of sprigs of fresh thyme; a couple of sprigs of fresh rosemary; 1 bay leaf; 1 teaspoon salt; 1/2 teaspoon freshly ground black pepper; pinch of saffron (optional), crumbled with your fingers or ground with a pestle and mortar; 2 small aubergines (400g), quartered then chopped into bite size pieces + 1 tablespoon salt; 1 large green bell pepper (200g), chopped into 1 cm pieces; 1 large courgette (300g), chopped into 2cm pieces