Toast the coriander and fennel seeds in small pan over a medium flame, shaking every 30 seconds so they don't burn. Once they've given off a lovely aroma and have turned a darker tone, remove from the hot pan and cool completely on a plate. Then throw them into your spice grinder and grind to a fine powder.
Mix the spices with the yogurt, tomato paste, ginger, garlic, hot sauce, brown sugar, salt, a healthy few grinds of freshly ground black pepper, apple cider vinegar, and oil. Taste and season according to your palate.
Cover each chop with the marinade, rubbing it into the meat and fat. You can marinate overnight, a few hours, or just 30 minutes. I've done all three and it tastes great every way.
Bake the chops in a 9- by 13-inch baking dish until the lamb is cooked to medium-rare, or to your liking, 15 to 20 minutes. Remove from the oven and allow to rest, tented with foil, for about 5 minutes before serving.