Coat both sides of the roast in oil, then season with the salt and pepper on both sides. Heat a large skillet over high heat (I like to use cast iron, but a non-stick skillet will also work well). Once the skillet is hot, sear each side of the roast for 4-5 minutes, allowing a golden brown crust to form. Place the roast in a slow cooker.
3-4 lb chuck roast, 1 ½ tablespoon olive or avocado oil, ½ teaspoon kosher salt, ½ teaspoon pepper
While the roast is searing, combine the tomato sauce, wine, soy sauce, and tomato paste in a liquid measuring cup or bowl. Once the roast is removed, pour the mixture into the hot pan. Simmer for 15-30 seconds, stirring continually to scrape up the brown bits on the bottom and help the tomato paste incorporate. Then pour this mixture into the slow cooker over the meat.
1 (15 oz) can tomato sauce, ½ cup dry white wine, 3 tablespoon soy sauce, 2 tablespoon tomato paste
Add the garlic, vinegar, oregano, cumin, smoked paprika, and red pepper flakes to the slow cooker. Swirl everything together a bit to help it combine.
1 tablespoon garlic, 1 tablespoon white vinegar, 2 teaspoon dried oregano, 2 teaspoon ground cumin, 1 teaspoon smoked paprika, ½ teaspoon red pepper flakes
Cook it on low for a total of 8-10 hours or high for 4-4.5 hours. When you have about 1 hour of cooking time left, add the onions and bell peppers to the crockpot, stirring to help coat them in the sauce. Then allow it to finish the last hour of cooking. The meat should fall apart easily when prodded with tongs or forks.
2 bell peppers, 1 large onion
Once tender, remove the meat from the crock pot and use two forks to shred it into medium chunks. Discard the fat. Stir the shredded meat and minced parsley back into the juices and serve warm with rice and beans.
2 tablespoon fresh parsley, For serving: White rice and Cuban black beans