Heat some vegetable oil in a large skillet over high heat. Add venison strips and sautÂ¿Â¿ for 5 minutes. Add salt and pepper, remove from pan, and keep on a warm plate. Place mushrooms and onion into the skillet and cook about 3 to 4 minutes. Add cream and let cook for 5 to 7 minutes. Add pickles, tomatoes, mustard, butter, and more salt and pepper if desired. Pour sauce over venison and serve.