Wow, sorry it took so long to pop into my head - but for all the people, and it seems there were like a dozen, who asked for mashed potato options: root for rutabaga, it's still not too late!
This humble tuber is absolutely delicious mashed. And so easy to make. It's standard fare in the British Isles, Ireland, and Scandinavian countries. So if that's your heritage, you should expose your kids to rutabaga.
Rutabaga is a turnip. But not the white/purple turnip. Rutabaga is brown/yellow and waxed. Peel it, chunk it, boil it in kosher/sea salted water until fork-tender. It takes longer than potatoes. Drain well. Easy to mash. Add plenty of unsalted butter and fresh ground black pepper. A nice variation, for when you're not serving a separate potato dish is to mix half cooked ptatoes into the cooked rutabaga and mash together - very traditional.
If you decide, like me, you love rutabaga, the other very traditional use for them is in Scotch Broth - a simple soup everyone should have in their repertoire - serious Northern European comfort food made with lamb stew meat, barley, carrots, celery, onions, bay leaf, just a bit of thyme.