Tear pieces of foil large enough to completely enclose each beet. Lay one piece of foil underneath each beet and drizzle each with a little bit of oil, sprinkle with a pinch of sea salt and a few grinds of black pepper.

Wrap each beet tightly in foil. You can double wrap them if they don't completely close, this way they will cook properly and won't make a mess in your slow cooker.

Place beets inside your slow cooker, cover and cook on high for 3-5 hours, or until tender. Remove from foil packets and slide the skin off, if desired (I didn't).