Place a rack in the upper third of the oven and preheat the oven to 450 degrees F.
For the lamb with herb crust: Place the parsley, olive oil, mustard, rosemary, garlic, lemon zest and juice and a generous amount of salt and pepper in the bowl of a food processor. Puree until the mixture becomes a paste. Spread the mixture all over the lamb (try to avoid the bones and get it all on the meat).
Place the lamb on a rimmed baking sheet bone-side up, and roast until an internal thermometer reaches 130 degrees F for medium rare, 15 to 20 minutes. Transfer the lamb to a cutting board, cover loosely with aluminum foil and let rest for about 10 minutes.
For the mint-basil pesto: While the meat is roasting and resting, place the mint, basil, parsley, lemon juice, honey, garlic and some salt and pepper in a clean food processor bowl. Puree to a paste; scrape down the sides of the food processor once and process again. Transfer to a serving bowl with a small spoon to serve.
Slice the racks of lamb into either single or double chops. Serve with the pesto passed on the side.