Preheat your oven to 400F and line a baking tray with parchment.
Wash and scrub the beets, pat it dry.
Peel the beets and then ‘hasselback’ your beets. To create accordion style cuts or hassleback, slice straight down into the beets, but stop just short of cutting it all the way through. Each slice can be between ¼ inch and 1/8 inch thick. For a fool proof method to slice the beets hasselback style place it on a wooden ladle or in between chopsticks. This will serve as a guide and prevent from cutting all the way through the beets.
Arrange the beets on the prepared baking sheet and fan the slices out as much as possible. Drizzle olive oil, season with a generous pinch of salt and pepper and let it roast in the oven for 1 hour - 1 hour 15 minutes. When they are done you want to ensure you can pierce them easily with a knife.
Prepare the Pesto
While the beets are in the oven, prepare the pesto. Add all the ingredients except olive into a food processor. Pulse a few times until everything is coarsely ground. With the motor running drizzle in the olive oil in a steady stream until the pesto is smooth and vibrant. Taste and adjust seasoning.
Spread the greek yogurt on a serving platter arrange the beets, drizzle the pesto and top with additional chopped pistachio.