- Place vegetables and broth in saucepan.
- Bring to boil, reduce heat, cover, and cook until vegetables are tender (about 8 minutes).
- Mix milk, cornstarch, salt, pepper, and thyme; add to cooked vegetables.
- Cook, stirring constantly, until soup is lightly thickened and mixture just begins to boil, about 5 minutes. Remove from heat. Add cheese and stir until melted.