I tried this one with venison tenderloin but it is a traditional Tuscan recipe used with wild boar. It was delicious. Credit to John Bishop of Bishop's in Vancouver, Canada.
Medallions of Venison with Savoury Chocolate Raisin Sauce
1 c. vegetable oil
2 T. fresh rosemary
1.5 lb venison
combine and marinade in refrigerator overnight.
2 T. butter
1/2 c. shallots, chopped fine
2 t. minced garlic
1/4 c. balsamic vinegar
1/2 c. red wine
1/4 c. fresh rosemary, chopped
2 c. veal demi-glace
Melt butter in saucepan, saute the shallots and garlic until tender. Add vinegar and reduce until almost gone. Add the red wine and rosemary, reduce by half. Add the demi-glace and simmer for 30 minutes. Strain. (This sauce may be made a day ahead and will taste better after the flavour has developed for a day. Refrigerate.)
1/4 c. raisins
1/4 c. white wine
2 T. cocoa powder
1/4 c. warm water
sea salt and freshly ground pepper
In a small bowl, soak raisins in wine for 2 to 3 hours. In another bowl, mix cocoa powder with warm water until smooth. Add water a little at a time to prevent lumping.
Remove venison from marinade and wipe off excess oil. Season. Heat a small amount of oil in heavy frying pan and sear venison for 1 or 2 minutes per side, until browned but still quite rare.
Venison cooked more than medium will be tough.
Remove from pan and put on plates. Add raisin and wine to deglaze pan. Add cocoa mixture, whisking until smooth, then add the sauce. Simmer until hot. Spoon over venison and serve.
I know you said you have a roast but you could cut it into cutlets. You actually didn't mention what cut you have? It should be a tender cut for this recipe.