1. Preheat the over to 450 degrees F. Line a baking pan with a piece of parchment paper.
2. Put the beet slices in a mixing bowl and toss thoroughly with the salt, thyme, and olive oil. Arrange the slices evenly on the pan.
3. Roast until the beets are tender and shrunken (10-18 minutes).
4. Serve warm or cold. Warm, they'll be crispy like chips. Cool, they'll be more like fruit leather.