Place potatoes and cold water in a microwave-safe bowl. Cover and microwave on high for about 1 to 1-1/2 minutes or until potatoes are tender; drain and set aside. In a small bowl, dissolve bouillon in boiling water; set aside.
In a saucepan, saute onion in butter until tender. Stir in flour until blended. Gradually stir in milk. Bring to a boil; cook and stir for 1-2 minutes or until thickened. Stir in the parsley, thyme, rosemary and garlic salt. Stir in potatoes and bouillon mixture; heat through.