1. Using a dutch oven or a soup pot add the butter and melt it on medium-high heat.
2. Add the onions, cook until soft and translucent (about 5 minutes) Stir frequently.
3. Add in the garlic, cooking for about 1 minute (or until fragrant). Stir often.
4. Increase temp to bring to a boil.
5. Add the flour, stirring often. Pour in the chicken broth.
6. Stir in the corned beef and sauerkraut.
7. Once it has boiled begin to reduce heat to a simmer.
8. Cover/ shimmer for 15 minutes.
9. Add the sour cream, chives and 1/2 of the shredded Swiss cheese. (1/2 of the 1 cup of cheese.) Stir well.
10. Cook for another 2-3 minutes for the cheese to melt.
11. Garnish with more Swiss cheese. Garnish with a rye bread croutons.