The Godmother's Famous Baked Onion Dip

INGREDIENTS

3 cups

chopped Vidalia onions (sweet onions), about 1½ large onions

1 cup

shredded sharp cheddar cheese

1 cup

shredded mozzarella cheese

1 1/2 cups

shredded Swiss cheese

1/2 tsp

garlic powder

1/4 tsp

black pepper

1 1/2 cups

mayonnaise

fresh chives to garnish (optional)

Tortilla chips for serving