You can stuff a thin steak with everything from bacon to cheese to mushroom duxelles. Whatever stuffing you choose, there's one key to a successful stuffed steak: Don't overstuff it. This is not the time when "more is better." Too much stuffing will just leak out of the steak into your grill and may make a rolled stuffed steak explode or break apart.
3 tablespoons apple cider vinegar
1/4 cup olive oil
1 tablespoon lemon juice
1 teaspoon dried basil
1/2 teaspoon dried oregano
1/4 teaspoon onion powder
1 tablespoon soy sauce
1 teaspoon salt
1/4 teaspoon garlic pepper
1 1/2 pounds flank steak
6 slices crisply cooked bacon, crumbled
1 ounce cream cheese, softened
1 cup grated cheddar cheese
1/3 cup crumbled feta cheese
1/2 cup diced roasted red bell peppers
8 8-inch bamboo skewers
Combine vinegar, oil, lemon juice, basil, oregano, onion powder, soy sauce, salt, and garlic pepper.
Pound steak to a 1/4-inch thickness. To flatten steak, start at the center of meat and pound toward the edges. Be careful to not tear or rip the meat; work slowly. Place steak on work surface with the grain running from right to left. This way you'll slice the meat against the grain. Place in large bag with marinade. Refrigerate for 12 to 18 hours. Drain, discarding marinade.
Combine bacon, cheeses, and bell pepper and spread on steak, roll up, and secure with 8 skewers. Place the skewers about 2 inches apart, starting 1 inch from each end. Be sure the skewers go straight through the meat. Cut evenly between each skewer with a sharp serrated knife, making sure to leave the same amount of beef on each side of each skewer.
Grill steak, turning once, over medium direct heat for 4 to 5 minutes per side until steak is medium rare.