Bring a large pot of salted water to a boil. Add the cavatappi and cook according to the package directions. Drain and rinse under cold water. Set aside.
Meanwhile, soak the onion in cold water for 5 minutes and then drain.
Whisk together the mayonnaise, sour cream, cider vinegar, sugar, mustard, drained red onion, 1/2 teaspoon salt and a few grinds of pepper until smooth.
Add the cooked cavatappi, tomatoes, dill, corn and zucchini to the dressing and stir to coat.
This recipe has been updated and may differ from what was originally published or broadcast.
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