The venison should be cut into medallions of 3 to 4 ounces, 1/2-inch thick and 3 inches across. Have all ingredients at the ready as this is a very quickly cooked saute method and the venison will over cook very quickly.
Heat the olive oil and butter in a large heavy skillet over medium heat until hot and foaming. Season the medallions with salt and pepper, and lay them in a single layer in the pan. Depending on the size of your skillet, you may need to do this in 2 batches. Char or sear quickly on each side for medium-rare.
Place the cooked venison on a warm platter and keep it warm while you make the pan sauce. Add the chopped shallots to the hot pan and saute for 2 minutes. Add half the green peppercorns and smash them quickly with the back of a spoon while sauteing with the shallots. Carefully add the brandy and de-glaze the pan. Observe caution when adding brandy to a hot pan and do this away from open flames to avoid flaming the brandy dangerously. Cook the brandy over low heat for 1 minute before adding the wine. Reduce the wine by half, add the stock, bring quickly to the boil and then swsirl in the cream for 1 minute. Add the medallions back to the finished sauce along with the remaining psppercorns and re-heat for 1 minute. Serve immediately.