Add the mustard, vinegar, honey and mint leaves and stir with a whisk to combine. Set aside
Roast the Brussels Sprouts
Preheat oven to 450°F. Toss the brussels sprouts and leeks with salt and pepper in the olive oil.
Roast for 15-20 minutes until crisp and bright green.
Lamb Chops
Add 1 tablespoon olive oil to a cast iron skillet and heat to super hot.
Add 4 lamb loin chops to the pan. Let it sear for about 3 minutes without moving. Turn over and sear for an additional 3 minutes. Add half the butter and half of the broth mixture. Cook about 1 more minute or until desired doneness. Remove to a platter to rest.
Cook the other batch of lamb loin chops in the same manner.
To serve
Place the brussels sprout on a platter, top with the seared lamb loin chops (top with a little butter if desired) and serve alongside the Mustard Mint Sauce.