Heat olive oil in a pan. Briefly fry the chicken fillets vigorously on both sides. Switch to medium temperature and finish frying in approx. 5-10 minutes per side. Season with salt and pepper. Take out of the pan and keep warm.
Heat the pan again and deglaze the meat stock with white wine. Let simmer briefly. Stir in the cream and mustard (Dijon mustard tastes very good). Season with dried tarragon or freshly chopped tarragon.
Bring the mustard cream to the boil while stirring and let it cook for about 2 minutes. Simmer until the mustard cream thickens.