Baking beets in the oven concentrates their sweetness and couldn't be easier.
Heat the oven to 400. Place however many scrubbed but untrimmed beets you like into a lidded casserole dish that they will fit into in a nice, snug way.
Add a half an inch of water, cover, and bake until the beets feel tender when you pierce them with the tip of a sharp knife. Depending on the size of your beets, this will take anywhere from 30 minutes (very small beets) to an hour and a half (very large beets).
Let the beets cool, then slice off their tops and rub the skins off under cold running water. Slice or cube, dress with a tablespoon of vinegar, then let them sit until you're ready to use them.