Mix mushrooms, liverwurst and bourbon. Set aside. Unroll crescent rolls, laying flat. Ensure that the seams are overlapped so there will be no leakage. Smear even layer of liverwurst mix over entire tenderloin. Cover tenderloin with crescent roll pastry. Brush outside with egg mixture. Bake in 425 degree oven for 25-30 minutes or longer in a lightly greased pan. (This time will result in rare-medium rare. Increase time if you desire medium-well and cover for the first 10 min to avoid too much browning). Remove and let rest for 10 minutes. Slice and serve with parsley garnish.
In this photo, it is served with Potatoes Au Gratin. Enjoy!