Preheat oven to 375°F (190°C) and line a baking sheet with parchment paper.
Scrub beets well (no peeling needed!) and slice very thinly with a sharp knife or mandolin.
Toss slices with a pinch of salt, lemon juice and zest. Let sit for 5 minutes.
Arrange in a single layer on the baking sheet and bake for 20-25 minutes, flipping halfway.
Cool completely (they crisp up more as they cool), then enjoy!