In a small bowl, mix together the salt, pepper, cayenne, cumin, and paprika.
Season the chuck roast generously on all sides with the spice mixture. Rub in the seasoning well to ensure the chuck roast is completely coated.
Heat a large skillet over medium-high heat. Sear the roast on all sides for about 2-3 minutes per side. Transfer the roast to the slow cooker. (Browning the roast is optional, but highly recommend for the best flavor).
In a small bowl, mix together the beef broth, tomato paste, and minced garlic. Pour the beef broth mixture over the roast in the slow cooker. Add the sliced jalapenos and half of the diced onions around the roast.
Cover and cook on LOW for 8 hours or on HIGH for 4-5 hours, until the meat is tender and shreds easily with a fork.
Once cooked, remove the roast from the slow cooker and shred the meat using two forks. Return the shredded beef to the slow cooker and stir well to coat with the cooking liquid. Mix in the freshly squeezed lime juice and the other half of the diced onions. Adjust the seasoning if necessary.
Warm the tortillas on a skillet or grill pan for 5-10 seconds on each side and set aside.
Spoon on some shredded beef with diced onions, and fresh cilantro or parsley. Add any other of your favorite taco toppings. Serve with limes wedges and enjoy!
Notes
Nutritional values do not include tortillas or toppings.
While browning the chuck roast before adding it to the slow cooker is optional, it is highly recommended as it adds a depth of flavor to the beef.
The level of heat in these tacos can easily be adjusted by altering the amount of cayenne pepper used and whether or not you choose to include the seeds from the jalapenos.
Both corn and flour tortillas work well with this recipe, though traditionally, street tacos are served on corn tortillas. Choose according to your preference.
These tacos are versatile. Feel free to add any additional toppings you love such as diced tomatoes, pickled red onions, or coleslaw.
Leftover shredded beef can be stored in an airtight container in the refrigerator for up to 3 days or frozen for up to 2 months. Reheat gently, adding a splash of beef broth or water to keep it moist.