In a large pot on medium heat, add the butter and sausage. Cook, stirring, until color and a light crust forms on most sides of the sausage, about 5 minutes. Add the pepper and onion blend and tomato paste and cook, stirring, until the bright red of the paste becomes a muted reddish brown, 5 to 8 minutes. Add the Cajun seasoning blend and cook it the same way as the tomato paste, ensuring the spices bloom and become fragrant. Add the stock, bring to a simmer and simmer, uncovered, for 15 minutes.
Pour over prepared rice and hit with a shake of your favorite hot sauce.