Take your beef roast, which can be a chuck roast or any other suitable cut, and sprinkle it with a generous amount of salt and pepper. This helps to enhance the flavor of the meat.
In a large skillet, heat some vegetable oil over medium-high heat. Once the oil is hot, carefully place the seasoned beef roast into the skillet. Allow the roast to cook for a few minutes on each side until it develops a brown, caramelized crust. This step helps to lock in the flavors and juices of the meat.
Prepare your slow cooker by combining the beef broth, which adds moisture and flavor, with pepperoncini peppers and their juice, which impart a tangy and slightly spicy taste. Add in diced onion, minced garlic, carrots, potatoes, fresh parsley, and thyme. These ingredients will add aromatic flavors to the dish and complement the beef.
Transfer the seared beef roast from the skillet to the slow cooker, placing it on top of the vegetable mixture. Ensure that the beef is nestled among the vegetables. Cover the slow cooker and set it to cook on low heat for 8 to 10 hours.
Carefully remove the cooked beef roast from the slow cooker and transfer it to a cutting board. Allow it to rest for 10 to 15 minutes. Resting the meat helps to retain its juices and ensures a more tender and succulent texture when sliced.
Slice the rested beef roast into thick slices and arrange them on a serving platter or individual plates. Surround the beef slices with the cooked vegetables and spoon some of the flavorful sauce from the slow cooker over the meat and vegetables.