Lay the out the prosciutto in 4 pairs of 2 pieces that are partially overlapping lengthwise. In a bowl toss the watercress with the oil, salt, and pepper. Divide the watercress equally in mounds placed at the end of the prosciutto slices. Wrap the prosciutto around the watercress and roll them up as tight as possible without bruising the watercress. Set aside. Slicing against the grain cut the beef into 8 equal slices. Lay each piece between 2 pieces of plastic wrap and lightly pound into tender thin pieces with a mallet or the side of a heavy knife or a wine bottle (with cork in it!).
Lay 2 pieces on each of the 4 salad plates. Drizzle the meat with the oil and season with salt and pepper. Place a roll of the prosciutto and watercress next to the beef. Place 1 (2-ounce) spoonful of the fresh goat cheese nestled between the beef and roulade. Garnish with the apple slices.