Add the oil to the inner pan of the Indoor Grill and preheat on high grill (500°F/260°C).
Combine the seasoning in a bowl and rub onto both sides of the chuck roast. When the grill has preheated and says, "add food," place the roast on the bottm of the inner pan. Close the lid and grill on high (or max grill if you want) for 5 minutes. Filp and grill another 5 minutes.
Cut your onion into chunks and add to the pan. Pour in 2 cups of beef stock and select the Roast function on 250°F/121°C and set the time for 3 hours.
I usually flip the roast every hour or so, but this isn't completely necessary.
After the 3 hours, remove the meat and make the gravy by combining the remaining beef stock and flour with some of the liquid in the pan into a large glass Mason jar or another glass container with a lid and shake until well combined. Pour into the pan. Put the roast in along with the vegetables and set the grill to the roast setting on 250°F/121°C for another 3 hours. The total cook time will depend on your roast, so start checking it after the 1st hour and give it a flip. It is ready when the meat is fork tender and the vegetables are done to your liking.