1Preheat your oven to 350°F (175°C).
Bring a large pot of water to a boil. Carefully remove the core from the cabbage and place the whole head in the boiling water. Cook for about 5 minutes, or until the outer leaves are tender. Remove the cabbage from the water and let it cool. Separate the leaves and set aside.
In a large bowl, combine the ground pork, cooked barley, chopped onion, minced garlic, chopped mushrooms, egg, salt, and black pepper. Mix well until all ingredients are evenly distributed.
Take a cabbage leaf and place about 2 tablespoons of the pork mixture in the center. Fold the sides of the leaf over the filling and roll it up tightly. Repeat with the remaining leaves and filling.
In a large baking dish, spread a thin layer of tomato sauce on the bottom. Place the cabbage rolls seam-side down in the dish. Pour the remaining tomato sauce and beef broth over the rolls.
Cover the dish with aluminum foil and bake in the preheated oven for 1 hour.
Remove the foil and bake for an additional 15 minutes, or until the cabbage is tender and the filling is cooked through.
Serve hot and enjoy your Cabbage Rolls with Mushrooms.