Boil one pound of rotini, salt water once the boiling process begins. Cook until tender, drain in serving bowl and chill. During the cooking time, thaw out the frozen peas and carrots.
Chop onion - only using this as added flavor.
Re-drain pasta once chilled, add peas and carrots, add at least six ounces of dressing, then toss in onion. Let set for a bit, add remaining dressing if pasta soaks up and residual. Add shredded cheese before serving. .