Vegetable Stock

• 1 large onion, stuck with whole cloves
• 2 carrots, sliced
• 2 leeks, chopped

Put all the ingredients into a large pan. Bring to the boil, then reduce the heat, cover and simmer for about 30 minutes. Cool slightly, then strain through a very fine sieve. Cool completely, refrigerate and use within 2 days, or freeze and keep for up to 3 months.