Start by bringing a large pot of water to a boil. Carefully place the whole cabbage head in the boiling water. Let it simmer for 5-7 minutes until the outer leaves soften.
Remove the cabbage from the boiling water and let it cool. Gently peel off the softened leaves, being careful not to tear them. Set them aside.
In a mixing bowl, combine the cooked rice, diced vegetables, minced garlic, chopped onion, oregano, and salt and pepper to taste. Mix them well.
Take a cabbage leaf and place a portion of the rice and vegetable mixture in the center. Fold the sides of the leaf inwards and roll it up, similar to a burrito.
Place the rolled cabbage leaves in a baking dish.
In a saucepan, heat the olive oil, then add the tomato sauce and vegetable broth. Bring to a simmer. Pour this mixture over the cabbage rolls in the baking dish.
Cover the dish with aluminum foil and bake in the oven at 350°F (175°C) for 45 minutes.
Once done, serve your delicious Vegetarian Stuffed Cabbage hot, and enjoy!