Zucchini, pea and ham bake

Ingredients

• 1 tablespoon olive oil
• 1 onion, chopped
• 2 cloves garlic, crushed
• 250 grams button mushrooms, quartered
• 2 zucchini, halved lengthways, sliced
• 1 1/2 tablespoon cornflour
• 1 1/2 cup (375ml) low-fat milk
• 1 1/2 cup (60g) low-fat tasty cheese, grated
• 4 cups cooked penne (from 1 1/3 cups raw)
• 1 cup (120g) frozen peas
• 1/2 cup (100g) low-fat ricotta, crumbled
• 150 grams ham, sliced
• 1 bunch chives, snipped
• 1/4 cup (20g) parmesan, grated