Bring a large pot of salted water to a boil. Add the potatoes and cook until tender, 15-20 minutes. Drain.
Melt the butter in the half-and-half over medium-low heat.
Place potatoes in the bowl of a mixer. Use the paddle attachment on low speed to mash the potatoes. Alternatively, mash the potatoes with a hand masher.
Slowly add the butter and half-and-half mixture, sour cream, and salt and pepper to taste. Mix until mashed but not smooth.
Stir in the vegetable and sausage mix from below.
Serve topped with warmed gravy.
To 'Cajunize' the potatoes
Heat the oil in a skillet over medium-high heat.
Add the sausage and brown, 4-5 minutes. Remove the sausage and all but 1 tablespoon of the fat.
Add the onion, celery, and green bell pepper and saute until tender, 5 minutes.
Add the sausage back to the pan and add the remaining ingredients. Stir.