In a large skillet over medium-high heat, brown the ground beef with the pepper and onion. Once the meat is cooked through and browned, add the garlic. Cook for an additional minute or so. Drain the excess grease away. Return the meat mixture to the skillet or a large bowl. Add the pepperoni, olives, and sauce. Stir to combine. Pour the meat mixture evenly into the prepared dish. Sprinkle the cheese evenly over the meat mixture. Open the crescent rolls, but do not separate them. Lay the dough, in one sheet, on top of the cheese. Pinch the seems together and then carefully stretch the dough to cover the top of the casserole. Brush with the melted butter, then sprinkle with the Parmesan cheese and Italian seasoning.