eight 12-inch metal skewers or bamboo skewers soaked in water 30 minutes
For the lamb and vegetables: Thread the eggplant slices onto 2 parallel skewers, piercing through the skin to stabilize the slices flat. Thread the zucchini slices the same way on 2 more skewers. Thread the onion slices the same way, piercing through the widest part of the slices. Finally, thread the tomatoes the same way, piercing though their equators with the stem sides facing up.
Place skewers on a sheet tray and drizzle and season all sides with olive oil, 1 teaspoon zaatar, salt and pepper.
Drizzle both sides of each lamb chop with olive oil and season with salt, pepper and remaining tablespoon zaatar.
Preheat a grill or grill pan for cooking over medium-high heat and heat a wide, heavy-bottomed braiser or Dutch oven over medium-high heat and drizzle with olive oil. Sear the lamb chops in the braiser for 3 to 4 minutes per side for medium, or until an instant-read thermometer inserted through the center of the meat (avoid bone) reads 135 degrees F. Cover with foil and let rest while you grill the vegetables.
Grill the eggplant and zucchini skewers, flipping once, until they have grill marks and are slightly tender, 3 to 5 minutes total. Meanwhile, grill the onion skewers, flipping once, until slightly charred and tender, 7 to 8 minutes total. Grill the tomatoes, flipping once, until they just start to burst and release their juices, 5 to 6 minutes total.
For Herb Sauce: Stir together the olive oil, vinegar, dill, mint, parsley, garlic, serrano and shallot in a small bowl. Season to taste with salt and pepper.
Remove the vegetables from the skewers to a serving platter or bowl. Place the lamb chops on a second platter and drizzle with the herb sauce and any juice left behind in the pan.