In a deep skillet or a Dutch oven heat 2 tablespoons oil over high heat. Add meat and break up with a wooden spoon, season with salt and pepper and poultry seasoning.
Place sweet potatoes in a pot, cover with water, cover pot, bring to a boil, salt and cook 15 minutes until tender.
Grate onions and carrots into the turkey. Add the celery and stir, cook 5 minutes. While vegetables are cooking, heat 2 tablespoons butter in a small pot over medium heat. Add flour to melted butter and whisk 1 minute then whisk in stock and season with salt, pepper and Worcestershire. Thicken a few minutes.
Stir the gravy into the turkey mixture. Stir peas into meat and turn heat off.
Drain potatoes and return pot to heat. Add remaining butter and melt over medium heat. Peel and slice banana and add potatoes to the pot. Season the potatoes with salt and pepper and a few dashes hot sauce. Mash potatoes and banana to combine, adjust seasoning. Top the meat with the potatoes. Cover potatoes with cheese and set in oven. Bake to melt cheese, 5 minutes.