It isn't thanksgiving without mashed potatoes (in fact, my oldest son contends that turkey is just an excuse to eat mashed potatoes with lots of gravy). The choices are many and all are pretty darn good. But among the glorious different spuds, it's helpful to know which ones, when mashed, will taste best. Potatoes with a high
starch content (such as russets) are drier,
mealier and more floury when cooked. They tend to fall apart so are better for
baking, mashing, and frying. These are your classic russet or baking potatoes, but they mash up fluffy and quick. Medium potatoes - Yukon Golds and Golden Finn potatoes have a lovely buttery color and though lower in starch, still mash up nicely. The low starch potatoes (boiling or red potatoes) are denser and better suited to roasting or using in a gratin (when mashed, they can become gluey). You can mash potatoes with the skins on (especially if they're organic) or peel and toss into the pot. I've had luck mashing the medium starch, yellow fleshed potatoes ahead, then simply warming them up in a casserole before serving. (Especially good if just glazed with a little melted butter before they go in to the oven.
The farmers markets and local store are now stocking plenty of potatoes and its a great time to stock up. Store potatoes, unwahsed, in a cool dry place. Before using, discard any that are beginning to green or grow sprouts, and scrub well. Peel (or not) throw into a pot and cover with water, add a bit of salt, simmer until very tender. Drain off the water and mash with milk (I've never bothered heating it) and butter as you please. At this point, taste and salt. For variety add a little horseradish or roasted garlic to taste or, mash in other cooked root vegetables, carrots, turnips or parsnips are great. Use up leftover mashed potatoes as a topping for a meat pie; add to soup as a thickner, or pat into cakes and saute off in a little butter. Around here, they don't last long and are often the last layer on a hot turkey sandwich.