Cook pasta according to the package directions.
Melt butter in a medium sauce pot. Once the butter is melted add cornstarch. Stir until smooth.
Cook over a medium-high flame until the mixture is smooth and bubbly, stirring constantly.
Add milk slowly, stirring until well blended. Add broth, cheese, garlic powder, parsley and pepper. Stir over a medium flame, until cheese is melted and the sauce is smooth.
Combine cooked pasta, alfredo sauce, and vegetables in a 13 x 9 greased baking dish.
Sprinkle with bread crumbs. Bake at 350 degrees for 20 minutes or until top is browned.