Preheat the oven to 220C, 200C Fan, Gas 7.
1. Heat a heavy based pan for 2-3 minutes.
While the pan is heating, rub a little oil over the chicken and season with
salt and pepper.
2. Colour the supremes on all sides until
golden and crispy, 2-3 minutes on each side. Place on a different tray and put
into the oven. Cook for 10-12 minutes. The chicken is cooked when its core
temperature reaches 75C or the juices run clear. Remove from the oven and cover
with foil, rest for 5-8 minutes
3. Return the pan to the heat and fry the
mushrooms until soft, deglaze the pan with the white wine. Boil the wine until
it is nearly evaporated. Add the chicken stock, mustard and tarragon. Reduce by
half, remove from the heat and whisk in the butter, it should become a smooth
and silky sauce. Season to taste with salt and pepper
4. Plate the chicken and serve with the sauce,
finish with some steamed broccoli and a glass of cold white wine.