Preheat oven to 350°F. Cook pasta as directed on package. Meanwhile, heat oil in large ovenproof skillet on medium-high heat. Add onions and mushrooms; cook and stir 5 min. or until onions are crisp-tender. Add zucchini and tomatoes with their liquid. Cook 10 min. or until most of the liquid has evaporated, stirring occasionally.

Mix pasta, eggs and 1/2 cup of the cheese in large bowl; mix well. Add to vegetables in skillet; stir until well blended. Cook on medium-low heat 5 min. or until bottom of frittata is set. Sprinkle with remaining 1/2 cup cheese.

Bake 10 min. or until center is set. Cut into 8 wedges to serve.