Fresh mashed potatoes are stirred together with sour cream and Cheddar cheese. A very small amount of sautéed onions is added for the flavor but it can be omitted upon request.  Oven:  25-30 minutes if thawed. 35 minutes if frozen.
 
Preparation:  Thaw completely. If frozen or partially frozen, add 10 minutes covered baking time.
 
Cooking Instructions:  Preheat oven to 350F. Place pan on baking sheet, and bake covered 20 minutes. Remove lid and bake additional 10 minutes. Potatoes should be bubbling on the edges. Allow casserole to sit 5-10 minutes before serving. Cooking times may vary due to differences in ovens.