Smoke the roast for 2.5 hours, or until the internal temperature reaches 160°F. When the timer is almost up, quarter the onions, then place the roast in a metal baking pan and surround it with the onions and garlic. Place the rosemary and thyme on top and a stick of butter on top of that.
2 large White onions, 6 cloves Garlic, 1 stick Butter, 3 sprigs Rosemary, 3 sprigs Thyme
Cover the roasting pan with foil, then place it back in the smoker and raise the temperature to 275°F. Cook for another 1.5 hours, or until the meat reaches 200°F.
Remove the pan from the smoker and remove the foil, then let the meat rest for 20 minutes. Slice, serve, and enjoy!
Notes
You can save on pellets by transferring the roast to the oven once it's covered in foil. It will cook just the same, as the smoke can't penetrate the foil.
It's critical that you let the roast rest for 10-20 minutes after it's done cooking. This lets the meat release and then re-absorb its juices, leading to juicy slices.
Reserve the juices left in the pan and use them for an easy beef gravy!
You can add extra vegetables to the pan such as potatoes, carrots, or other hard vegetables, but the onions and garlic are a must.
Because beef chuck contains so much fat and connective tissue, it's naturally so juicy that it doesn't need to be spritzed with apple juice or beef broth while smoking. However, it doesn't hurt to give it a spritz now and then if you desire.