1In a large pan, add the chopped onions with a splash of olive oil, plus salt and pepper. Let the onions cook on low heat for 30 minutes, stirring occasionally.
2After 30 minutes, add 1/2 cup of beef broth and 1/4 cup of sherry, and let the onions cook an additional 15 minutes.
3Add the remaining 1/4 cup of beef broth and 1/4 cup of sherry. Add the softened cream cheese and 3/4 cup of cheese, stirring until melted.
4Transfer the mixture to an oven-safe dish and top with the remaining 3/4 cup of cheese.
5Bake for 15 minutes. For a crispier topping, broil on high for 2-4 minutes.