Melt 2 Tbsp. butter in a large kettle
Add onion, carrots, and celery. Saute until slightly tender.
Add chicken broth (or water) and potatoes. Cook until almost tender.
Add broccoli and cauliflower (optional) and cook until the florets are al dente
Add seasonings (Thyme, S & P, garlic powder)
While vegetables are cooking, use a different kettle and melt butter (4 Tbsp)
Add flour and stir until smooth (a whisk works best)
Add milk and cream. Stir until smooth and keep stirring until the mixture thickens
Add both cheeses and stir until melted
Pour into the kettle with the vegetables. Stir well.
Heat until warm all the way through. Serve