Bring a large pan of salted water to the boil, add the potatoes and cook for 20 mins or until tender.
Meanwhile, crush the garlic with 1 tsp salt, using a pestle and mortar, to form a paste.
Drain the potatoes and allow to steam-dry for a couple of mins, then pass them through a ricer into a bowl (or see tip, below). Stir in the garlic paste and gradually add the olive oil, mixing thoroughly until you have creamy, light potatoes.
Stir through the red wine vinegar and the tapenade. Keep warm under foil until ready to serve. This recipe goes well with Rosie's slow-roasted shoulder of lamb and braised summer veg. See recipes, right.
Easy mashingIf you don't have a ricer, you can push the cooked potatoes through a sieve using the back of a ladle to get the same effect. For more tips on making mashed potato, watch the video here.