Step 1 Turn on a food processor and drop in the garlic. When it is chopped, turn off the machine and scrape down the sides. Add the olives, capers, anchovies, thyme, rosemary and mustard. Blend together until fairly smooth. Add the lemon juice, olive oil, a generous grinding of pepper and the Cognac and continue to blend until you have a smooth paste.
Step 2 Scrape the tapenade into a serving bowl and garnish with the herbs. Refrigerate 2 hours until ready to serve.