I just made twice baked potatoes - and started by adding 3 tsps. of unsalted butter to the meat of 5 large baking potatoes. After adding the butter and starting to mash some of the potatoes, I did a taste test - tasted kind of "off". I then thought to look at the expiration date on the butter - 4 years ago!!! I finished the assembly with regular fresh butter sour cream, etc. and the potatoes taste fine.
Question: will eating these make my family sick? Should I throw them out and start all over?