Follow the steps in order for the best result.
In a bowl, whisk together the olive oil, lemon zest, lemon juice (from one lemon), and crushed garlic to create the marinade. Place the lamb racks into the marinade, ensuring they are well coated. Allow the lamb to marinate in the refrigerator for at least 2 hours, or longer for enhanced flavor.
Remove the lamb from the marinade and drain off any excess liquid. Using a sharp knife, score the fat cap of each rack in a diamond pattern. This will help render the fat and create a beautiful presentation.
Place a cake rack inside a baking dish. Position the lamb racks on the cake rack. This elevation prevents the lamb from sitting directly in its rendered fat during cooking, promoting even browning.
In a small saucepan, gently warm the dark honey and the juice of one lemon until combined. Do not boil.
Brush the honey-lemon mixture generously over the fat cap of each lamb rack. Sprinkle fennel seeds evenly over the glazed surface.
Preheat your oven to 350°F (175°C). Bake the lamb racks for approximately 30 to 40 minutes, or until they reach your desired level of doneness. For medium-rare, aim for an internal temperature of 130-135°F (54-57°C). Baste the lamb racks regularly with the remaining honey-lemon mixture throughout the baking process to ensure a beautifully caramelized glaze.
Once cooked, remove the lamb from the oven and let it rest for 10 minutes before carving. This allows the juices to redistribute, resulting in a more tender and flavorful final product.