Vidalia Onion Dip

2 cups chopped Vidalia onion
2 cups mayonnaise
2 cups shredded Swiss cheese
2 cups grated Parmesan cheese

1. Preheat oven to 325 degrees F.

2. Stir together all ingredients and spread in a 2-quart baking dish. Bake until the top is golden brown and bubbling, about 1 hour. Serve immediately with a variety of pita chips, crackers, pretzels, carrots, and celery.