Preheat oven to 400 degrees.
Lightly grease a large baking sheet.
Saute your onions in the butter until golden, set aside.
Cook your meat just until done, season with salt and pepper.
Work your dough gently into a rectangle shape. I find quickly turning it (like a steering wheel) and allowing the dough's own to weight stretch it into a rectangular shape while it hangs briefly, works for me.
Once dough is shaped to your liking. place it on a large piece of parchment or waxed paper.
Season the inside area if the dough with a bit of salt and pepper,
Scatter your fried onions over-top the dough, keeping 1/2 inch or so of the perimeter of the pizza dough bare.
Place the steak slices across the stromboli top, allowing for a 1/2 inch bare perimeter of dough.
Season with salt & pepper.
Place slices of American or Provolone atop the steak.
Gently begin to roll (from the long edge) until you form a stromboli. Pinch seam and ends closed.
Bake for 25-30 minutes or until the top is golden brown and crisp.
Allow the stromboli to sit for a few minutes, then slice into pieces and serve with pizza sauce for dipping.