Mustard Mashed Potatoes

Mashed potatoes are always a good accompaniment to any saucy dish, and mustard is a good foil to a rich dish like the Tail and Tongue Stew. These are really pureed potatoes, as they are put through a food mill. I’m prepared to take this extra step because the texture is better, but if you just want to mash, that’s fine too. The amount of mustard is a matter of taste; the puree should taste of potato first, then mustard. I bring Dijon mustard back from