Remove marinated oxtail from refrigerator at least 20 minutes prior to cooking.
Heat olive oil over medium-high heat in a cast-iron skillet or stew pot and sear oxtail 2-3 minutes per side, until they are brown in color.
Remove from skillet/pot and allow oxtail to rest.
Add 1 tablespoon of extra-virgin olive oil to pot then add chopped onion and sauté until golden brown.
Carefully scrape up any brown bits from the bottom of pan into the mixture with a wooden spoon or spatula. This adds more flavor!
Add in blended tomato mixture and cook for 2 minutes.
Pour in beef broth and stir in well. Next, add tomato paste and butter. Stir well. Cook for an additional 5 minutes.
Add in cayenne pepper, smoked paprika, and crushed red peppers.
Add oxtail back to the stew pot. Cover and cook for 5-10 minutes over medium-high heat. Stirring occasionally.
Reduce to low heat, stir, and add cover. Cook on low heat until oxtail is tender (about 2 hours for beef).
In the last half hour of cook time, add in sweet potato chunks and bell peppers. Taste and adjust for salt if needed.
Serve and enjoy!
