Sauté carrots and onions in olive oil until tender.
Add corned beef/pastrami, chicken stock, garlic powder, sauerkraut, heavy cream, AP rub, celery salt, butter and pepper and simmer for 10 minutes.
Ladle out about 1 cup of the hot broth into a separate bowl and whisk in corn starch to create a roux.
Stir roux back into the soup and simmer until soup has thickened.
Just before serving, melt in the baby swiss for extra tang and creaminess.
Serve with toasted rye bread.
Enjoy!