Pre-heat the oven to 200°C / 400°F / Gas Mark 6.
First mark the duck breasts with a sharp knife, all the way across in both directions (lattice like) all you want to do is score the fat, not cut right the way through, so the fat crisps when you roast it.
Pre-heat a tray or an oven proof pan on top of the stove with oil, season the duck breasts then place skin side down, colour well, turn over and colour the other side. Then place skin side down and place in the oven, turn over after a couple of minutes, then take out after 10-12 minutes and let rest.
To make the celeriac puree, peel and cut the celeriac into reasonable size pieces. Boil in salted water for about 15 minutes until tender, drain and shake well. Puree with a little butter, salt and pepper, then push through a sieve to get a smooth textured puree, if you wanted it a little richer then you could add a little cream.
For the sauce take your red wine, sugar and bring to the boil, add cranberries, cook for 1 minute then take out half of the cranberries, cook the rest for a few minutes. Add the beef jus, reduce slightly and pass through a sieve, then add the rest of the cranberries, and keep hot (don't boil).
