Preheat your oven to 375°F (190°C).

Bring a large pot of salted water to a boil. Carefully remove 8-12 large leaves from the cabbage head. Blanch the leaves in boiling water for 2-3 minutes until pliable, then drain and set aside to cool on paper towels.

In a large mixing bowl, combine the raw Italian sausage, cooked rice, diced onion, minced garlic, beaten egg, Parmesan cheese, oregano, salt, and pepper. Mix by hand until well combined.

Pour about 1 cup of the marinara sauce and the chicken broth into the bottom of a large 9x13 inch baking dish and stir slightly to combine.

Take a cooled cabbage leaf and trim the thickest part of the rib at the base to make rolling easier. Place roughly 1/3 cup of the meat mixture in the center of the leaf.

Fold the sides of the leaf over the filling and roll it up tightly from the stem end.

Place the cabbage roll seam-side down in the prepared baking dish. Repeat this process with the remaining leaves and filling.

Pour the remaining marinara sauce evenly over the top of the rolls.

Cover the dish tightly with aluminum foil and bake for 50-60 minutes, or until the cabbage is tender and the sausage is fully cooked (internal temperature reaches 160°F).

Remove from the oven, let rest for 5 minutes, and garnish with chopped fresh parsley before serving.