Slash the fat on the duck breast and then sear it on both sides in a very hot pan.
Remove it from the pan and place in the oven at 180C/350F/Gas 4 for about 10 minutes.
Meanwhile, drain off any excess fat from the frying pan. Put in the shallots, garlic, thyme and tomatoes and cook for a minute or two.
Deglaze the pan with the balsamic vinegar and red wine. Add the butter and redcurrants and reduce the sauce for a couple of minutes.
Remove the duck from the oven to rest, then slice on the diagonal. Serve with the sauce drizzled over it and some crusty French bread.