Melt butter in a Dutch oven over medium-high heat; add bell pepper and the next 3 ingredients, and saute 4 to 5 minutes or until tender. Add potatoes and cumin, and saute 5 minutes or until browned and tender.
Gradually stir in broth; stirring to loosen particles from the bottom of Dutch oven. Bring to a boil; cover; reduce heat to low, and simmer 25 minutes.
Whisk together flour and the next 2 ingredients. Stir into the potato mixture, and cook over medium heat, stirring constantly, 5 minutes or until thickened. Reduce heat to low.
Add cheeses, and cook, stirring constantly, until cheeses melt and mixture is thoroughly heated. Serve with desired toppings.