Preheat oven to 350 degrees.
Place beets in a baking pan with high sides. A 9 x 9 stainless steel pan should be good if you're only roasting a few beets; use a larger pan if you have more or the beets are quite large. The sides should be as tall as the beets are.
Pour kosher salt on top of the beets until they are covered completely. (You will most likely NOT use the entire box of salt, but it will take plenty!)
Cover pan with foil.
Bake for 1 hour; check for doneness. A fork should sink into the beets once they are fully cooked. Add more time if necessary.
Remove from oven and allow to cool/rest for at least 30 minutes before handling.
Once the beets are cool enough the handle, the skin should be loose enough to wipe right off. Use a clean kitchen towel to do so. (Heads up – the salt and beet color may destroy/bleach the towel, so pick your towel accordingly!)
Slice or chop the beets to your liking and serve.