Rub the lamb with thyme, if using. Sprinkle with garlic, salt, and pepper. In a zip-top bag, coat with oil on all sides. Squeeze out as much air as you can from the bag and seal.

Marinate at room temperature for two hours or in the refrigerator overnight. If refrigerating, remove from the fridge two hours before cooking to bring to room temperature.

Preheat oven to 450 degrees Fahrenheit.

Place the lamb in a baking dish and bake for 10 minutes, until browned (see note). Reduce oven temperature to 300 degrees Fahrenheit and bake another 15–20 minutes.

In a saucepan, heat the oil over medium heat. Add the lamb fat and sauté for 10 minutes. Remove the bits of fat from the pan. Add the shallots and garlic and sauté another three to four minutes. Add the wine, salt, and pepper and bring to a boil. Add the potato starch dissolved in water and cook for 10 minutes. Add the cherry tomatoes

and cook for three to four minutes. Set the sauce aside.

In a blender, pulse the pistachios, oil, and salt until they form a paste (there should still be some larger pieces of pistachios). Coat the sides of the lamb, slice the racks in half, and serve with the sauce.