Zesty Skillet Ratatouille

eggplant, cut in bite size pieces

Kraft Zesty Italian Salad Dressing, divided

coarsely chopped onion

green bell pepper, coarsely chopped

garlic, minced

small zucchinis, sliced ¼ inch thick

small yellow squash, sliced ¼ inch thick

Roma tomatoes, deseeded and cut in bite size pieces

chopped mushrooms