1. Put the frozen roast inside the crockpot and pour the broth on top. Then, combine the spices and seasonings in a bowl, and spread on top of the meat.
2. Cover the slow cooker and set the program at HIGH for six hours. At the five-hour mark, open the crockpot and add the vegetables and onion.
3. At the six-hour mark, check the carrots and potatoes for fork-tenderness, and observe the meat. You should have the beef easily come apart when pulled with a fork.
4. Transfer the meat to a serving plate and let it rest for five minutes.
5. Meanwhile, transfer the pan juice into a saucepan over medium heat, add ground black pepper, and stir.
6. Make a slurry from cornstarch and water, add it to the pan juice, and stir until it thickens.

Serve the roast along with the gravy and vegetables.

You can also watch this video for more help.