Wash the beets extremely well. You will not want to peel your beets because drying them with the skin on keeps them more round and pretty. (Yes, I’m that vain when it comes to food!) Also, there’s a tonne of nutrients in the skin. Cut off the bottom end of each beet and thinly slice the beet with using a mandolin. You’ll want to get the beet slices as evenly cut as possible so that they all dry at the same amount of time.
Once the beets are all sliced, place them in a large bowl and drizzle very lightly with olive oil. Arrange the sliced beets on a large baking sheets, being careful not to overlap the beets. Sprinkle with kosher salt.
Place the beets in the oven and set the temperature to 200 degrees.
Check the beets every 30 minutes and using tongs, carefully turn each beet over to even the baking process.
You will note that with each turn, the beets are reducing quite drastically in size. This is normal!
At the two hour mark, remove one slice from the oven, allow it to slightly cool, and feel the texture of the beet with your fingers. The beet will not be crispy at this time, but should feel dry and have a slight pliable texture to it. If this is the case, remove the dried beets from the oven. If not, feel free to leave them in the oven for another 30 minutes. Continue to do this until the right consistency has been reached. Don't worry, the pliable texture will change to a chip-like texture once the beets have cooled.
Place the cooked, warm beet slices in a large mixing bowl. Add the desired amount of dried thyme (about 1/2 teaspoon) and toss to coat the beets evenly. Allow to cool.