French Onion Soup

Name: French Onion Soup
Ingredients: 8 brown onions, sliced; 30 g butter; 1 tablespoon olive oil; 1 tablespoon thyme leaves; 2 tablespoons plain (all-purpose) flour; 2 tablespoons brandy; 2 tablespoons Dijon mustard; 2 litres beef stock; 2 cups (500ml) water; cheese sandwiches or parmesan toasts, to serve