Debates rage over whether gumbo is a stew or soup, but we do know that it originated in Louisiana, and is found across the Gulf Coast and the South. It consists of a strong stock, meat and/or shellfish, and the vegetable "holy trinity" of celery, bell peppers, and onion. It is thickened with okra, file powder, or a roux. A roux is a combination of flour and most often butter that is cooked in a pan. Very dark roux that has cooked for a long time if essential for flavor and has less thickening power. Thick or thin, gumbo is traditionally served over rice.