Preheat the oven to 350°F (175°C).
Bring a large pot of water to a boil. Core the cabbage and carefully separate the leaves. Blanch the cabbage leaves in boiling water for 2-3 minutes until pliable. Drain and set aside to cool.
In a large bowl, combine ground beef, cooked rice, chopped onion, minced garlic, egg, salt, black pepper, paprika, and dried thyme. Mix thoroughly until all ingredients are well incorporated.
Trim the thick vein from the base of each cabbage leaf to make rolling easier.
Place about 2-3 tablespoons of the meat mixture in the center of each cabbage leaf. Fold the sides over the filling and roll up tightly, tucking in the edges to secure the filling.
In a large oven-safe baking dish, heat olive oil over medium heat. Arrange the cabbage rolls seam side down in the dish.
In a separate bowl, mix tomato sauce, beef broth, and lemon juice. Pour this sauce evenly over the cabbage rolls.
Cover the baking dish tightly with aluminum foil and bake in the preheated oven for 1 hour.
Remove the foil and bake uncovered for an additional 15 minutes to allow the sauce to thicken slightly.
Remove from oven and let the cabbage rolls rest for 10 minutes before serving.