Place veggies and broth in 3 qt or larger saucepan. Bring to boil, reduce heat, cover and cook till veggies are tender, about 8 minutes.
Mix milk, cornstarch, salt, pepper and thyme; add to cooked veggies. Cook, stirring constantly, till slightly thickened and mixture just beings to boil. Remove from heat. Add cheese and stir until melted.