3 cups freshly shredded cheese (I use 1.5 cups mild cheddar and 1.5 cups mozzarella but you can use all cheddar if you like)
4 ounces cream cheese, cubed
2-3 small Vidalia or other sweet yellow onion, diced
½ cup mayonnaise
Place cubed cream cheese in large mixing bowl and microwave for about thirty seconds, just until soft.
Add diced onion, cheeses, and mayo to mixing bowl with cream cheese. Stir to combine.
Spoon into greased 1.5 baking dish (8×8 works fine)
Bake at 375 for 25-30 minutes, or until bubbly and lightly browned on top.
Serve with corn chips or crackers.Source : allrecipes.com