Preheat the oven to 400 degrees F. Place a cast iron skillet on the bottom rack of the oven.
Cut the tops and root end off of the beets. Set the greens aside for salads. Use a sharp knife and peel the skin off.
Cut each beet in half; quarters for larger ones.
With a sharp knife, make thin cuts on the top side of the beet (where the skin was), stopping just before you fully cut through. (See photo above in post for an example)
Drizzle a bit of olive oil in the hot skillet and swirl it around to coat the bottom.
Place the beets in the skillet and drizzle olive oil over each beet. Lightly tent with foil.
Roast for 25 minutes, or until you can easily pierce the beet with the tip of a knife.
Top with crumbled goat cheese, chopped hazelnuts, and a generous pinch of salt.
Notes
You can peel and "Hassleback" them up to three days before roasting. Just make sure you store them in an air-tight container.