Place all ingredients in a food processor. Pulse to break up, then process for 30 seconds until the mixture resembles crumbs. Scrape sides if necessary. Process for another 1-2 minutes until a ball is formed.
Line an 8×8 baking dish with parchment paper. Wet fingers (to prevent sticking) and press mixture into square baking dish. Refrigerate for at least one hour. Slice bars into 8 pieces and store in the refrigerator until ready to eat.