Bake 14 to 16 min. or until edges are almost set. Top with 1/2 cup cheese, ham and remaining cheese. Bake 2 to 4 min. or until cheese is melted. Meanwhile, mix all remaining ingredients except English muffins in microwaveable bowl until blended. Microwave on HIGH 1-1/2 min. or until heated through, stirring every 30 sec. Meanwhile, toast muffin halves.