Peel and chop onions. Then saute the onions in the butter. Let onions cool. Beat eggs and sour cream together and add to onion mix. Stir in salt and pepper. Pour into a 9 by 11 inches baking pan. spread cheese on the top. Bake for 20 min at 450, then reduce heat to 325 and bake an additional 20 minute.
Optional: Add hot pepper sause to taste with the salt and pepper to give it a less sweet taste and a little kick.