How to Make It
Preheat the oven to 400°. In a large roasting pan, combine the venison scraps and bones with the carrots, celery, onion, and 2 tablespoons of the oil; toss well. Roast the vegetables and meat for 30 to 40 minutes, stirring occasionally, until well browned. Transfer the contents of the roasting pan to a large saucepan.
Set the roasting pan over two burners. Add the vinegar and deglaze the pan over moderate heat, scraping to loosen the browned bits. Pour the vinegar into the saucepan and add the veal stock, wine, parsley, thyme, juniper berries, bay leaves and 1 tablespoon of the peppercorns. Simmer over moderately low heat, skimming occasionally, until very flavorful, about 1 hour.
Meanwhile, in a small skillet, combine the remaining 2 tablespoons of oil with the flour. With a wooden spoon, stir the mixture over moderately low heat until light brown, about 5 minutes. Scrape the roux into a bowl.
Once the sauce has reduced, whisk 1 cup into the roux; whisk the roux mixture into the simmering sauce until thoroughly blended. Cook over very low heat for 45 minutes, whisking occasionally. Add the beach plum jelly and simmer for 15 minutes. Strain the sauce into a medium saucepan and then add the remaining 1 tablespoon of peppercorns.
Add any juices reserved from carving the venison and whisk in the butter, 1 tablespoon at a time. Season with salt and serve with the venison.