This is a REALLY simple recipe, and you can interchange the ingredients with a variety of things.  For me, the combination of the roasted peppers, prosciutto, and the provolone cheese melting as the meat cooks was just sublime!  I used toothpicks to hold the roll together, it would be MUCH easier to tie it off every 2 inches or so with cotton cooks twine.
Ingredients:
About 1 lb of flank steak
1 package thin sliced prosciutto
About 4 slices jarred roasted red peppers
4 or 5 slices thick cut provolone cheese
Several leaves of  fresh basil
Handful of spinach leaves
Salt, pepper, garlic powder to taste
Directions:
Lay the flank steak out on a large piece of waxed paper, and fold it over to cover completely.  Hammer steak out with a meat mallet, till it is about ½ inch thick.  Lay out on a plate.
Season with fresh kosher salt, fresh ground pepper, and just a sprinkling of garlic powder ( a little of this goes a LONG way)
Lay Prosciutto strips out so entire steak is covered, lay red peppers so entire steak is covered, spread Basil and spinach leaves over peppers, and finally cover all of it with slices of cheese.
Roll the steak as tight as you can, pin closed with toothpics.  Tie with cotton butchers twine every two inches or so, to keep steak rolled up. Remove toothpicks.
Grill over med – med/high heat for about 20 minutes, turning every 5 minutes or so to brown all 4 sides.  Cooking times vary by grill, so use a meat thermometer to be sure it is done – should be about 150 or 160 degrees for medium.
Serve sliced about ¾ of an inch thick, with grilled veggies and a salad….. a simple, awesome summer meal!