Preheat the sous vide machine to 57*c. Vacuum two racks per bag with a clove of garlic, teaspoon of mustard and rosemary. Cook for 1-2h (until vegetables are done)

Cut potato in wedges and cook in water on low heat for 15min

Drain potatoes well, put in a roasting pan with quarteres onions and remaining unpeeled garlic. Cover all in olive oil, season and roast on 220*c for 30min