Melt the butter in a large sauté pan and gently fry the sliced onion, leek and garlic.
Pour in the sherry, bring to the boil and bubble for a few minutes to boil off the alcohol.
Add the stock and crème fraiche and simmer until reduced to about half.
In a separate frying pan, fry the pancetta or streaky bacon strips until crispy.
Add the shallots and mushrooms to the crispy bacon and fry for a few minutes until softened.
Add the contents of the frying pan to the sauté pan. In the empty frying pan, gently fry the slices of chicken until golden brown on both sides.
Add to the sauté pan. Deglaze the frying pan with a little water and add to the chicken mixture in the sauté pan. Add the thyme and Dijon mustard to the sauté pan, stir, season and simmer gently for 10 minutes.
4 chicken breasts sliced diagonally into 4 pieces each
Knob of butter
1 onion sliced
1 leek sliced
2 garlic cloves chopped
½ pint/300ml amontillado sherry
½ pint/300ml chicken stock
100ml half fat crème fraiche
10 shallots peeled and halved
1 tablespoon fresh thyme leaves
1 pack (150g approx) button mushrooms
4oz/100g pancetta or smoked streaky bacon cut into strips
1tsp Dijon mustard
Fresh chopped parsley to serve