Add beets and carrot to a blender or food processor and process until finely ground. Set aside.
Brown sausage and onions over medium-high heat in a large heavy bottom pot. Add ground beets and carrots and sauté for an additional 3 minutes, stirring occasionally.
Add chicken broth, thyme, and beans. Reduce heat to medium and bring to a simmer and simmer for 20 minutes, stirring occasionally.
Remove from heat, remove thyme, and season to taste. Top with sour cream if using. Enjoy.
Notes
If you can, make the soup in a heavy bottomed pan or dutch oven. It will distribute heat more evenly and the bottom is less likely to catch.
I use the blender to grind my beets and carrots so it has a similar texture to the Italian sausage. You can skip this step and finely chop the beets and carrots or grate them on the side of a box grater.
You can use chicken, beef, or vegetable broth in this recipe.
If storing, let the soup cool completely before placing in a container.