So you're making Thanksgiving dinner for 20 people and you're wondering whether you can make the mashed potatoes ahead of time and keep them warm. The answer is yes!

Here are four foolproof methods to keep your mashed potatoes warm (or reheat the ones you made yesterday). The method you use is up to you; use the one that works best for you and your schedule.

The Slow Cooker Won't Let You Down

Mashed potatoes do get stiff and gluey once they sit for too long. And while we'll eat them cold and hard straight from the refrigerator, obviously you want them to be fluffy and creamy on your Thanksgiving table. But making them at the last minute isn't always an option, and they cool down fast.

We like to make mashed potatoes first thing on Thanksgiving, and keep them warm throughout the day. (If you'd like to make them the day before, check out the first alternate method below.)

For our first, and favorite, method for keeping mashed potatoes warm and delicious, the secret, as you may have guessed, is the slow cooker.

No Slow Cooker? Here Are 3 More Methods

1. If you want to make potatoes a day ahead and reheat them.

We've made mashed potatoes the day before Thanksgiving and re-warmed them with great success.

Add a healthy extra dose of cream and butter, so that the potatoes are almost soupy. You want them to just about drip off the end of a spoon. Put them in a deep casserole or soufflé dish — even a Dutch oven will do — and store in the fridge overnight. Warm them up in the oven the next day, uncovered, with a little butter on top. The extra moisture will evaporate and you'll have creamy potatoes. If you're really nervous about the outcome, do a test run to see how much extra liquid you need to add to get the consistency you want.

2. If you just need to keep them warm for an hour.

Another tip that we've used before is to set your bowl of potatoes over a pot of simmering water, just like a double boiler. Cover the top of the bowl with plastic wrap or (our choice) a dish towel. Give it a stir every 15 minutes or so to keep the mixture well-heated.

3. If you just need to keep them warm for 20 minutes.

If you only need to keep the potatoes warm for about 20 minutes, we've simply covered the bowl with a dishtowel and let it sit. We usually make our mashed potatoes in our standing mixer, so we just throw a towel over the top of the mixing bowl and the potatoes stay plenty warm for up to 30 minutes.