Pre-heat oven to 450 degrees
Place heavy Dutch oven with lid over high heat
Take the roast and rub the Cajun seasoning, onion powder, garlic powder and flour
Put olive oil in the Dutch oven
Put roast in the oven and let it brown on both sides
Throw in carrots and onions
Pour onion soup and chicken stock to cover
Bring to a boil
Place cover on and place in oven
Decrease oven temperature to 375 degrees and cook until the meat falls apart (3 to 4 hours)
If the gravy needs to be thickened, stir in Wondra flour until desired thickness