Bring a large pot of water to a boil. Add the whole head of napa cabbage and cook for 2-3 minutes until the leaves are softened.
Remove the cabbage leaves one by one and set aside.
In a bowl, combine the shrimp, cooked rice, onion, garlic, soy sauce, sesame oil, salt and pepper.
Place a spoonful of the shrimp mixture onto each cabbage leaf. Roll up the leaf and secure with a toothpick.
Place the cabbage rolls in a baking dish and bake at 375°F for 20-25 minutes until heated through.
