Ingredients

  • 1 pound top round beef, cut into 1-inch pieces
  • 1 tablespoon Worcestershire sauce
  • 2 teaspoons Montreal steak seasoning
  • 1 tablespoon extra-virgin olive oil
  • 2 small sweet onions, sliced
  • 1/3 cup balsamic vinegar
  • 1/4 teaspoon salt
  • 1/4 teaspoon cracked black pepper
  • 1 teaspoon canola oil
  • 4 (6 inch) submarine sandwich roll, split
  • 6 ounces Brie cheese, torn into pieces

Method

  • Stir beef, Worcestershire sauce, and Montreal steak seasoning together in a bowl. Marinate beef while preparing other items.
  • Heat olive oil in skillet over high heat. Cook and stir onions in hot oil until golden brown, about 15 minutes; add balsamic vinegar, salt, and black pepper. Reduce heat to low and cook the onion mixture at a simmer until there is little liquid remaining and the mixture is syrup-like in texture, about 10 minutes.
  • Preheat an outdoor grill to 400 degrees F (200 degrees C) and lightly oil the grate.
  • Remove steak pieces from the marinade and shake off excess. Discard the remaining marinade. Combine beef and canola oil in a bowl and toss to coat.
  • Preheat oven to 200 degrees F (95 degrees C).
  • Cook the beef slices on the hot grill, turning frequently, until they start to firm and are reddish-pink and juicy in the center, 4 to 6 minutes per side. An instant-read thermometer inserted into the center should read 130 degrees F (54 degrees C).
  • Arrange rolls onto a baking sheet. Spoon onions into the bottom of the sandwich rolls; add beef. Top beef with Brie cheese.
  • Heat in preheated oven until the cheese melts, about 5 minutes.