1. Place the beef tips and oil in hot skillet and saute until beef is cooked as you like.
2. Pour gravy and broth into the skillet with beef, stir, turn heat down to simmer and continue cooking for 10 minutes.
3. In separate pan, heat margarine over medium heat, then add mashed potatoes, stirring until heated through. Salt and pepper to taste.
4. Put mashed potatoes on plate and top with beef tip mixture.