Place the venison in a deep dish. Peel the onion for the marinade and slice over the meat. Add the bay leaf, peppercorns, lightly crushed juniper berries and a few parsley stalks. Pour over the red wine and oil. Leave to marinate for 12 hours or overnight, turning the meat and basting from time to time. Drain and pat dry and reserve the marinade.
Melt the dripping in a large frying pan.