Preheat broiler 450 degrees. Place an oven rack a few inches from the heating element.
Combine 1 tablespoon of oil with coriander, cinnamon, ginger, garlic, 1 teaspoon salt, and ¼ teaspoon pepper. Coat London with spice mixture. Let it marinate for 20 minutes.
Coat a cast iron or oven-proof skillet with canola or vegetable oil. Heat over high heat. When the skillet is very hot, sear the London broil on both sides (you may want to turn on your exhaust fan before doing this).
If you like your steak rare, check it for doneness once it’s seared. However, if you like your steak medium rare to well done, place it under the boiler to continue cooking until it reaches your desired doneness. Our steak was a beautiful medium rare after XX minutes.
Remove London broil from the oven. Allow it to rest for 10 minutes before slicing it against the grain. Serve with any accumulated pan juices poured over top.