Scrub the beets and rinse well under running water. Trim off the beet tops and roots. Save the greens for other recipes.
Preheat oven to 300˚F. Spray two baking sheets with non-stick spray or line with parchment paper.
Use the slicing disk of a food processor, mandolin v-slicer, or knife to slice the beets thin, try to get them around 1/16-inch (3 mm) thin.
Place the beet slices in a large bowl. Keep each color separate so the colors don't bleed.
Toss the beets with 1 teaspoon salt and let them sit for 10 minutes to sweat out excess moisture. Drain the liquid, and pat the slices dry with paper towels.
Drizzle with olive oil and sprinkle with onion powder, garlic powder, and pepper. Toss to coat evenly.
Lay the slices out in a single layer on the prepared baking sheets. Bake in a preheated oven for about 15-20 minutes until crisp up around the edges. Start checking after 15 minutes. Depending on the thickness of your slices and natural sugars in your beets, they may crisp up quicker.
Remove the beet chips from the oven and cool on a cooling rack. The beet chips will crisp up as they cool.
And add more salt to taste, if desired. Serve immediately, or cool completely and store in an airtight container for up to 2 weeks.