this is a really hard one - so many of them are staples for me. In selecting a favorite i gotta make clear that basically every other option was a serious contender.
At the end o the day it has to be the beet. It's such a joy to cook with beets. they're gorgeous on their own (just slicing em up into a salad reveals some really beautiful interiors) and when they cook i love the way their juice permeates everything around them resulting in a lot of beautiful shades of red and pink. they taste damn good raw, stir fried, pickled. Beet eggs are maybe the best thing you can do with a hard boiled egg. i love em a lot