Prepare a smoker with wood or pellets (preferably hickory or apple wood) to 225℉/107℃.

In a mixing bowl, combine salt, sugar, crushed black pepper, cajun powder, garlic powder, onion powder, cumin seeds, paprika powder, and crushed chili powder. Use a whisk to blend thoroughly. Store in a cool, dry place for future use.

Use a knife to trim excess fat from the beef, Spread olive oil evenly over beef, Sprinkle marinade powder evenly over the surface of the beef.

To ensure accuracy, insert the probe into the thickest part of the meat, making sure the safety line is completely immersed.

Select beef→ roast→ chuck in the parameters list. Set the target temperature to 200℉/93℃.

Transfer the beef into your preheated smoker, then securely close the lid.

To begin the process, simply press the start button on your phone. Roast for 3 hours, basting with 1 cup beef broth every hour (reserve the other 2 cups).

Place the chopped onions in the bottom of a large disposable foil pan and pour the remaining 2 cups of stock into the bottom of the pan. Place the roast in the pan on top of the onions and place the pan on the grill.

Increase grill temperature to 250℉ and roast until internal temperature reaches 165 ℉ (approximately 3 more hours). Once roast reaches 165 degrees, cover pan tightly with foil and continue cooking until the target temperature reaches 200 ℉.

Carefully remove the beef and place it on a heat resistant surface. Let it rest for at least 15 minutes.

Carefully remove the probe.

Separate the roast from the cooking liquid. Shred the roast and separate the fat from the cooking liquid. Use the remaining cooking liquid to moisten the roast.