• 600 g (1 lb 5 oz) assorted mushrooms
• 20 ml (½ fl oz) grape seed oil
• 4 brown onions, chopped
• 5 garlic cloves, chopped
• 70 g (2½ oz) sea lettuce
• 1 litre (35 fl oz) chicken stock
• 5 g (⅛ oz) salt
• 60 ml (2 fl oz) white soy sauce

Preheat the oven to 60°C (140°F). Slice the mushrooms as thinly as possible, arrange in a single layer on a baking tray and place in the low oven for 5 hours to dehydrate.

Heat the oil in a saucepan and sauté the onions and garlic lightly. Add the dry mushrooms, sea lettuce and chicken stock and cover tightly with plastic wrap. Infuse over low heat for 6 hours without boiling or uncovering.

When ready, strain through muslin (cheesecloth), discarding the solids. Season with the salt and white soy sauce.