Preheat oven to 375.
Line baking sheets with foil and spritz with olive oil.
Peel and slice beets into 1/8 thick rounds. Try to be consistent for even baking.
Spritz beets with olive oil.
Toss with Rosemary and Sea Salt
Bake for about 20 minutes. Flip beats over. Bake another 15 minutes, monitoring closely.
If they aren't done to your liking, bake in 5 minute increments. They burn quickly, so keep a close eye on them.