Break the feta into large chunks and place it in the bowl of a food processor fitted with the metal blade.
Add in the Greek yogurt and lemon zest.
Turn the food processor on. While it is blending, slowly add olive oil through the tube.
Blend until smooth, no more than 40-45 seconds, stopping halfway through to scrape the sides as needed.
Transfer to a bowl and garnish with fresh herbs. Finish with a light drizzle of olive oil and a sprinkle of sumac or red pepper flakes.
