Good news! We’re having Rack of Lamb for dinner tonight! I’ve been preparing rack of lamb this way, seared in a hot skillet, then coated with garlic and herbs and roasted in the oven since my days as a personal chef, more than 20 years ago!
Meanwhile, trim the rack of lamb by cutting the excess fat between the rib bones, stopping at the bulk of the lean loin. Cut away excess fat cap, leaving some fat on the outside edge of the lamb. Sprinkle salt and pepper.
Stir garlic and herbs in a small dish. Feel free to do this ahead if you like. Just keep it in an airtight container in the refrigerator for a couple of days.
Heat the oil in a heavy oven-proof skillet over high heat. Add the lamb, fat side down, and let it sear until the meat is browned. This will make a lot of smoke, so turn your fume hood on high.
Flip the rack over, and then spread the mustard over the seared meat. Pat the garlic and herb mixture over the mustard (or simply the herbs if using the roasted garlic as your under layer.)
Let the rack of lamb rest for as long as you need while you prepare your side dishes. Place it on the carving board and tent generously with foil. Then carve between the rib bones into individual lamb chops.