How can I fix mashed Idaho® potatoes ahead of time?

Here is what I would do: peel the raw potatoes, cut into chunks (about ½ inch makes the boiling go fast, usually 20-25 minutes). Place in a pan with cold water, covering the potatoes and boil until fork tender (can you crush them with a fork?). Once cooked, drain into a sieve or colander, place in an ice bath with lemon juice, water and some ice cubes for a couple of minutes. Drain, put the potatoes into a plastic tub with a lid or a big plastic bag and refrigerate overnight.

The next day, heat up using a microwave or a slow cooker, then add in the hot liquids, mix and serve. I love the slow cooker to keep food warm, not just to cook in it. It frees up the stove top and the oven for other foods.