Fry enough bacon very gently to extract enough fat to fry the medallions. Remove the bacon. Put enough well-seasoned flour into a plastic bag and toss the venison in it; remove and lay on some greaseproof paper.
Heat the bacon fat and fry the meat on a medium heat for 5 to 7 minutes, turning frequently. Put them in a warmed dish with a teaspoon of jelly on each medallion and keep warm while you make the sauce.
If you are using blackberries instead of jelly, cook them lightly in a little red wine and sugar to taste. Spoon over the medallions as for the jelly.
Depending on how much you are cooking, add enough of the stock to the pan. Boil briskly, stirring all the juices together. When it starts to look syrupy, mix in enough sour cream to make a rich sauce. Adjust the seasoning. Pour over the venison.
Serve with tiny Brussels sprouts and egg noodles with chestnuts if handy. Apple sauce can also be added as a side dish.