Preheat oven to 350 degrees.
Pat the frozen onions dry with a paper towel.
Combine the thawed frozen onions, 1 small chopped onion, cream cheese, Parmesan, and mayo in a bowl.
Mix well so there are no large clumps of cream cheese.
Spoon onion mixture into a baking dish and bake for 20-30 minutes or until heated through.
Serve with assorted party crackers. Serves 25.