How to Make It
Preheat oven to 375°. Place the spices in a medium bowl and toss to combine. Add the spices on a large baking sheet lined with parchment and toast for 10 to 15 minutes, until the spices are aromatic. Transfer to a spice grinder and grind until coarse, but not too fine.
Preheat oven to 400°. Line one large baking sheet with parchment paper and drizzle with olive oil, and season with salt and pepper on the surface. Place the shallots cut side down. Roast the shallots for 30 to 40 minutes or until completely soft and tender.
Heat an oven to 400°. Temper the beef and season with salt and pepper. Allow to come to room temperature. Season with Roasting Spice liberally on all sides.
In a large roasting pan, heat a small film of canola oil over medium high heat. The pan will begin to smoke. Add the beef, and begin to roast in the pan. Allow the beef to caramelize over medium to medium high heat. Flip the beef to the other side and repeat. Add the butter, garlic, and herbs once caramelized, and baste for 2 minutes.
Place the beef onto a roasting rack and cook in the oven until the internal temperature reaches 125° for medium rare, about 10 minutes for properly tempered beef. Allow to rest for 8 to 10 minutes.
Dress the watercress with the vinegar and olive oil and season with salt and pepper in a small bowl.
Slice the steak off the bone then into 6 larger slices crosswise. Season with fleur de sel and fresh cracked black pepper. Place into a serving dish and arrange with the lemon, watercress, and shallots.