Storage: Store cooled soup in airtight containers in the fridge for 3-4 days. Keep croutons separate and dry. Soup can be frozen (cream may separate; stir well after reheating).
Variations: Use roast beef, pastrami, or mushrooms for different takes. Russian dressing or a DIY mix of mayo, ketchup, and relish works if you don’t have Thousand Island. Swap in half & half for a lighter soup.
For best texture, use freshly shredded Swiss and drain sauerkraut well!