In Provence, tapenade is traditionally prepared with salt-cured olives that have been packed in olive oil. The olives and all the other ingredients are crushed and blended into a paste by hand in a marble mortar with a pestle. If you lack salt-cured olives and a marble mortar, an acceptable version of tapenade can be made with well-drained canned black olives in a blender. Put the olives and the anchovies in a blender or food processor and chop them. Add the capers and chop again. Finally add the mustard and olive oil and blend to a paste.