Melt butter in a frying pan.

Season the chicken breasts with salt and pepper.

Cook the chicken for 10 to 15 minutes on each side until nearly done.

Grate in the garlic cloves and continue frying.

Turn the heat up to high and add the red wine vinegar.

Boil for one minute to let the chicken absorb the flavour of the vinegar.

Remove the chicken from the pan, cover with aluminum foil and place it in a dish in a warm (not hot) oven.

Add the shallots to the juices and vinegar remaining in the frying pan.

Cook, stirring constantly, until the shallots are nearly translucent.

Add the wine and the tomato puree.

Bring this mixture to a boil and boil until it reduces by half, stirring all the while.

When the mixture has reduced, lower the heat and stir in the cream.

Add the mustard.

Put the chicken back in the pan and turn to coat it in the sauce.

Serve the chicken with a bit of sauce on top, and pour any remaining sauce in a container to serve at the table.

I like to serve this with roast baby new potatoes (Jersey Royals this time of year), but it is equally delicious with boiled potatoes or rice.