Cover beets with cold water, bring to the boil and cook for about 30-40 minutes until tender. I usually cook the beets in my electric pressure cooker, about 8-10 minutes. Electric pressure cookers cook at 12lbs/psi not 15 lbs of regular pressure cooker, so times need to be adjusted - I add roughly 20% more time for electric pressure cooker and write times in cookery book. I've never been happy with roasting beets and why would I turn the oven on just for a few beets.
When cool enough to handle, rub skins off beets, they will stain your hands.
I cut my beets into tiny cubes and use the fine shredding blade of my food processor to approximate the tiny pieces of beet from Café Sofra. Large cubes would have shredded into long pieces like coleslaw. You can also just cut peeled, cooked beet into small cubes for more texture and not shred. I have also shredded the cooked beet in a small hand held cheese grater, like the French moulinex grater or Zylis cheese grater. I have tried peeling the raw beet, cutting it into small cubes with a fluted cutter and pan frying. It still took over 30 minutes to gently pan fry with some oil.
I often put all the fresh herbs in a coffee mug and use sharp scissors to chop as fine as I like. This is quicker than knife on a chopping board. And doesn't stain chopping board.
In a mixing bowl, combine all ingredients except beets. Stir well and add beets. Season to taste with additional salt and pepper. Chill until ready to serve. The original recipe used far more yogurt in relation to beets.