1. dice the onions and place in a pan with 1/2 cup butter and caramelize them.
2. add 1/2 teaspoon salt and pepper.
3. cut potatoes and boil till soft , once they are done strain completely and add remaining butter and sour cream using a hand blender blend together
4. when onions are done add to potatoes and blend together with the cheese the heat from the onions will help melt the cheese.
5. salt and pepper to taste.