Saute butter and onion on medium heat until the onion is soft. Add the garlic and potatoes and stir occasionally until potatoes are coated in the butter and the garlic is fragrant.
Add the mixture to a large crock pot along with the carrots, broth, and seasonings. Cook on low for 6 hours or high for 3 hours (potatoes should be fully fork tender).
Use an immersion blender and blend until smooth. Add the cream, cheese, broccoli, and more salt & pepper.
Serve topped with more cheese and crumbled bacon if desired.
