In a large saucepan or stockpot, bring the 100ml olive oil, the vermouth and 150ml cold water to the boil with the bouquet garni and a pinch of salt and simmer for 10 minutes. Taste for saltiness and adjust accordingly.
Working with 1 artichoke at a time, remove 2 or 3 layers of the outer leaves until the inner pale green ones appear. Cut off the top 3cm of the