How to Make It
Using a paring knife, cut a few 1/4-inch-deep slashes in each lamb chop. In a large bowl, whisk the yogurt with the heavy cream, lemon juice, ginger, garlic, malt vinegar, garam masala, cumin, paprika, cayenne, mace, nutmeg and 1 teaspoon of salt. Transfer the lamb chops to the marinade and turn to coat, then cover and refrigerate overnight.
Add the oil to the marinade and toss with the lamb chops. Remove the chops from the marinade and let stand at room temperature for 30 minutes.
Light a grill. Season the chops with salt and grill over moderately high heat for 8 minutes, turning once, until well browned. Brush both sides of the chops with the melted butter and grill for another 2 minutes per side for medium-rare.