I'm cooking steak au poivre on New Year's Day and I'll be making a salad and mashed potatoes to accompany it. I'd like to make the mashed potatoes ahead of time, so that I can enjoy my aperitif with my dinner guest and not deal with anything but the steak and sauce when the time comes. I assume I can keep the potatoes warm in a slow cooker set on low heat. However, how long can I keep them in the slow cooker? I don't want them to turn to glue or become otherwise taste-comprimised? Could I keep them in there for 3 or so hours? Any help is appreciated!