Soak the mushrooms in 300ml hot
water for 10 mins until plump. Drain,
reserving the soaking liquid, and chop.
Mix with the butter and half the tarragon,
then stuff under the skin of the chicken.
Heat oven to 200C/180C fan/gas 6. Heat
the oil in a large flameproof dish, add the
chicken and brown on all sides. Transfer
to the oven for 20 mins. Remove from the
oven; the chicken should be cooked by
now. Remove from dish and keep warm.
Return the dish to the heat, add the
wine and simmer until nearly reduced.
Add the reserved mushroom liquid and
simmer to reduce by half. Stir in the
crème fraîche and simmer for 1-2 mins
more. Add the remaining tarragon and
season. Return the chicken to the dish,
heat through for 1 min more, then serve.