Preheat the oven to 300°F. Line several baking sheets with parchment paper or spray with non-stick spray.

Scrub the beets well under cold water, trim off the greens and roots, but leave the skins on. Use a mandoline slicer to slice the beets 1/16-inch thin. If using different color beets, place them in separate bowls to prevent bleeding.

Place the beet slices in a large bowl. Drizzle with olive oil and sprinkle with salt (and optional spices like onion powder, garlic powder, and pepper, or the warm spice mixture if desired). Toss to coat evenly.

Let the beets sit in the oil and salt for 10-20 minutes to sweat out excess moisture. Drain off any released liquid and pat the slices dry with paper towels.

Lay the slices out in a single layer on the prepared baking sheets, being careful not to overlap. Use enough baking sheets so beets don’t overlap.

Bake in the preheated oven for 15-60 minutes, rotating sheets from top to bottom halfway through baking if using multiple sheets. Bake until the edges begin to dry and curl, and the chips are crisp but not brown. Cooking time will vary depending on thickness and oven.

Remove the beet chips from the oven and allow them to cool completely on the pan or a cooling rack. They will crisp up further as they cool.

Once cool, transfer to a platter or bowl. Sprinkle with more salt to taste, if desired.