Chicken chasseur

1.For slow-cooked celery heart, heat a large saucepan of water to 65C. Heat oil in a large saucepan over medium heat, add carrot, leek and onion, sauté until tender (8-10 minutes), add chicken stock, set aside to cool. Divide celery heart, vegetables and stock between two vacuum bags, seal, cook in water bath until tender (35-40 minutes). Remove, keep warm.

2.Meanwhile, preheat another large saucepan of water to 80C. Divide chicken breasts between five large vacuum bags, divide stock, wine, tarragon, tomato paste and porcini powder between them, seal, cook in water bath until cooked through and tender (30-40 minutes), then set aside to rest.

3.Meanwhile, for white wine and tarragon sauce, place garlic in a small saucepan, cover with cold water, bring to the boil over high heat, drain, repeat three times. Heat duck fat in a small saucepan to 80C, add garlic, cook until tender (10-15 minutes). Strain through a sieve (reserve duck fat for another use), mash garlic with a fork until smooth, set aside. Meanwhile, heat butter in a saucepan over medium heat, add porcini powder, deglaze with wine. Add stock and tarragon, bring to the simmer and reduce by half (40-45 minutes). Whisk in cream and garlic purée, season to taste, strain through a fine sieve, keep warm.

4.Heat half the butter in a large frying pan over medium-high heat, add half the mushrooms and shallot and sauté until tender (8-10 minutes). Set aside, then repeat with remaining butter, mushrooms and shallots. Return reserved mushrooms to pan, add tomato, season to taste and keep warm.

5.Divide celery among plates, top with chicken breast (add poaching liquid to sauce), scatter over mushroom mixture, drizzle with white wine and tarragon sauce and serve.