Rinse quinoa and add with broth to a sauce pan with a tight fitting lid. Bring to a boil, reduce heat to low, cover and simmer for 15 minutes. Turn off heat and let sit for 3-4 minutes before removing lid. Do not let quinoa sit longer while covered or it will get mushy.
Heat a large pot of salted water separately over high heat to bring to a boil. Add whole head of cabbage, cover and reduce heat to low. Boil cabbage for 10 minutes and then remove from pot using oven mitts or two large spatulas. Set aside to cool.
While quinoa and cabbage are cooking, heat oil over medium-high heat. Add onion and carrot and sauté for 3-4 minutes to soften. Add garlic and sauté a minute longer before adding turkey. Cook turkey for 6-7 minutes until fully cooked. While cooking, use a spatula to break the turkey up into small pieces. You do NOT want large pieces of turkey, only small crumbles.
While turkey cooks, add worcestershire, salt, pepper, paprika, and 1/2 cup of the marinara sauce. Add cooked quinoa to turkey mixture and stir to combine. Taste and adjust seasoning levels if desired. Add egg and stir to mix in.
Spoon about 1/2 cup of the marinara sauce into a 9 X 13" casserole dish and spread out to thinly cover the bottom of the baking dish.
Peel leaves from cabbage carefully to keep intact. Scoop 1/2 - 3/4 cup turkey filling into the center of a cabbage leaf. Fold the bottom half over the filling and then tuck the sides in. Fold the upper half over and lay seam side down in the prepared casserole dish. Repeat with remaining cabbage leaves until dish is full and filling is gone (typically 10 rolls).
Spread remaining marinara sauce on top of cabbage rolls and bake for approximately 30 minutes. Serve hot with sour cream or plain yogurt.
Nutrition facts are per roll, not per serving (usually 2 rolls).