Prepare the lamb marinade first. In a small bowl, combine olive oil, herbs, garlic and Dijon mustard. Place lamb chops on a sheet pan and season with salt and pepper. Spoon marinade over lamb chops making sure to coat both sides well. Let sit for at least 30 minutes or even overnight in the refrigerator. Be sure to remove from refrigerator at least 30-45 minutes before grilling.
Prepare the Pistachio Herb Sauce while the lamb is marinating. Place all sauce ingredients in a food processor and process until well blended. Taste and adjust if necessary with salt, pepper and lemon juice.
When grill is hot, cook lamb chops about 3-5 minutes per side for medium rare or until desired doneness. Let rest 5 minutes, then serve with Pistachio Herb Sauce. Serves 4.