Water
Heat oven to 400F, and roast oxtails until browned, about 30 minutes. Heat oil in a large pot over medium flame. Add onions and carrots. Cook until onions are translucent. Add tomatoes and cook until they deepen in color and smell sweet, just a few minutes. Add oxtails and all remaining ingredients with just enough water to cover (if using potatoes, add them near the end of cooking time so they don’t get mushy).