Preheat oven to 350°F. Heat 2 tablespoon olive oil in large sauté pan over medium heat. Add pancetta and cook until it's browned and crispy, about 5 minutes. Add the onions and crushed red pepper and cook until onions are translucent, about 5 minutes. With 1 minute remaining, add garlic. Remove and let cool.
Mix together the breadcrumbs, cheese, parsley and pepper. Stir in the pancetta onion mixture until everything is combined. Set aside.
Lay the flank steak flat and pound until about ¼" thick. Sprinkle the breadcrumb mixture evenly to cover the steak. Starting at the short end, roll up the steak like you would a jelly roll to enclose the filling. Using some butcher's twice, tie the steak to secure. Sprinkle the braciole with salt and pepper.
Heat remaining 2 tablespoon of olive oil in a large Dutch oven over medium heat. Add the braciole and cook until browned on all sides, about 2 minutes per side. Add the wine and bring to a boil and stir in the marinara sauce. Cover and cook in the oven for 2 hours or until the meat is tender. Baste with the sauce very 30 minutes and remove the cover with 30 minutes remaining.
Remove the twine and cut the braciole crosswise and diagonally. Transfer to a plate and spoon sauce over to serve.
Use qualityflank steak. Beef is the star here, so don't go cheap on it. If you have a butcher that can cut it for you, take advantage and ask them to cut about ¼ inch in thickness.
Take your frustrations out on the flank steak and pound with a meat tenderizer. Flank steak is tough, so pounding it will help tenderize it and make it melt in your mouth when you cook it.
Use fresh provolone and Parmesan cheese. Do not buy pre-shredded cheese. Just try pre-shredded vs. blocks of cheese and side-by-side and you'll notice the difference.
Cover your flank steak with a thick coat of the breadcrumb mixture. This is where the flavor comes in so don't skimp it.
When rolling the flank steak, start at the short end and roll as tight as possible. If some of the breadcrumb mixture comes out no problem. That means you put plenty!
Use a friend or sous chef to help you tie the butcher's twine around the flank steak. Don't tie it so tight you squeeze everything out. You want to tie it where it just holds the flank steak together. I usually use 5 pieces of twine.
Make sure you sear the flank steak on all sides, so every side is browned nicely. It takes about 2 minutes per side. Searing meat is all about building flavor and texture so don't skip it!
Use quality dry red wine for sauce. When adding wine to a sauce, it has to be something you're willing to drink. I usually go with Chianti or Pinot Noir.
Use your favorite store-bought marinara sauce. The flavor comes from the steak and the wine.
Cut the braciole crosswise and diagonally into ½ inch slices so it is tender and melts in your mouth.