In a food processor, chop the onion, garlic and bell pepper.
Set the stockpot over medium heat. Once it's hot, add the oxtail and brown all sides, rendering some of the fat.
Remove the oxtail. Pour in the chopped onion and garlic mixture along with the sazon, cumin, bay leaves and salt, and sauté quickly. After 5 to 10 minutes, add the oxtail back in.
Add the tomato sauce and coat the oxtail in the sauce and onion mixture. Let that cook for 10 to 15 minutes, then reduce to low or medium heat depending on your stovetop.
Once the onion and garlic mixture is slightly caramelized, add the bone broth and water, stir, and cover.
Monitor and adjust the heat if needed. Make sure the mixture is cooking without burning, and stir. Cover and continue cooking until the oxtail is fork tender and slightly falling off the bone.
Spoon off any excess fat from the top of the stew. Oxtail is fatty and quite a bit will rise to the surface as it cooks.
Peel and chop the potatoes, then add them to the stew to finish cooking for 10 minutes.
Finish with cilantro if you'd like.
Serve with freshly cooked white rice and enjoy. Buen provecho!
