Makes about 2 litres of stock
Heat 30ml (2 tbsp) of sunflower oil in a large pot and add 1 chopped onion, 3 chopped leeks, 3 chopped carrots, 2 chopped parsnips and 3 chopped celery sticks. Toss to coat, cover and cook, 3 – 5 minutes.
Add 2,5L of water and bring to a boil. Skim the surface and add 3 bay leaves, a few peppercorns, 2 garlic cloves and 45ml (3 tbsp) fresh flat-leaf parsley. Reduce heat and simmer, about 1 hour.
Sieve the stock into a clean bowl, pressing the solids to extract all of the liquid. Set aside to cool and freeze until needed.