Put the liver and onions on warm serving platter. Pour over the liver and onions and serve immediately. Do not cut through the opposite side of the roast. Open roast and lay flat. Drain tomatoes, reserving 3 tablespoons oil.
Place tomatoes evenly over basil.
Place roast on rack in shallow roasting pan. Carve roast into 1-inch slices. Arrange on serving platter and garnish with tomato roses. Serve with roasting juices. Toss the meat with the peanut oil and thread on skewers in an accordion or zig zag fashion.