Add butter to the CanCooker and melt on a medium-to-medium low heat.
Add onion and garlic and sauté until soft and tender, about 3-4 minutes.
Add flour and mix well until evenly combined with the onion mixture and continue to cook for one minute.
Pour in chicken stock and Italian seasoning. Mix well and simmer for 3-4 minutes
Add in mashed potatoes and stir until the potatoes have broken up. Let the soup simmer over medium heat for 8-10minutes until thickened, stirring occasionally.
Add turkey and half and half cream. Cook until heated through about 3-5 minutes.
Stir in corn and season with salt and pepper to taste.
Ladle into bowls and top with shredded cheddar cheese and parsley if desired.