Preheat oven to 425 F, and oil or grease a casserole dish.
In a deep skillet over medium high heat add ground turkey meat, poultry seasoning,sea salt, and pepper.
Break up meat and seasonings with a wooden spoon and brown the meat.
Place sweet potatoes in large stock pot and cover with water, bring to a boil, lower heat slightly, and cover pot and cook for 15 minutes until tender, or fo low carb steam or microwave riced cauliflower until soft (4 minutes), Set aside.
Add to ground turkey meat: grated carrots, chopped celery, and mushrooms.
Stir meat and veggies while cooking over medium high heat for about 6 minutes or until tender.
While veggies are cooking, Melt 2 tbsp coconut oil, or butter in small sauce pan overt medium heat.
Add 2 tbsp sifted coconut flour, or 2 tbsp cream cheese to the oil / butter sauce pan, and whisk for one minute.
Whisk in 1 cup chicken stock to sauce pan, and add garlic powder, dash sea salt and pepper, and Worcestershire sauce*optional.
Let thicken a few minutes ( coconut flour version will not get very thick, but it still works).
Stir chicken stock gravy mixture into turkey meat veggie mixture.
Turn off heat from turkey skillet.
Drain sweet potatoes and return to the warm stock pot ( if using cauliflower, then squeeze out moisture from steamed cauliflower pressing it, wrapped in a cheese cloth or fine mesh towel and continue to follow directions using in place of sweet potato.).
Add 2 tbsp coconut oil or 2 tbsp butter to sweet potatoes and melt over medium heat.
Add peeled sliced 1/2 banana, sea salt, pepper, cayenne pepper sauce.
Mash sweet potato and banana with potato masher or electric beater until combined.
spread turkey meat mixture on bottom of casserole dish, then top and spread with sweet potato mixture.
Can top with optional cheese.
Bake in 425 F oven for 20 minutes or until slightly browned.