Pre-heat oven to 325F
Saute the onions and mushrooms in butter in a pan on medium heat.
Remove the pan from the heat and wait 5 minutes until cooled.
Add the onion and mushroom mixture to a baking dish and add the softened cream cheese, egg, salt and pepper and mix well.
Bake for 25 minutes until creamy and bubbly.
Serve hot with crackers or sliced veggies!