1.Heat half the oil in 6-litre (24-cup) pressure cooker. Cook mushrooms until browned lightly. Remove from cooker.
2.Heat remaining oil in cooker. Stir onion, garlic and half the basil over heat until onion softens. Add eggplant, capsicum, zucchini, undrained tomatoes and water; secure lid. Bring cooker to high pressure. Reduce heat to stabilise pressure and cook 5 minutes.
3.Release pressure using the quick release method and remove lid. Add mushrooms. Simmer with lid off until hot. Season to taste. Serve soup sprinkled with remaining basil.
If you have an electric pressure cooker you won’t need to reduce the heat to stabilise pressure, your cooker will automatically stabilise itself. Always check with the manufacturer’s instructions before using. Recipe not suitable to freeze.Note