Season the steak rather liberally with kosher salt. Bring it to room temperature, about 1 hour outside of the fridge.
Preheat the oven to 325 degrees F.
Combine the paprika, cumin, mustard and a few turns of freshly cracked pepper in a small bowl. Season the steak with the rub.
Heat the canola oil in a saute pan over high heat until smoking. Add the steak and sear on all sides, about 3 minutes per side. Add the butter, thyme, rosemary and garlic. Reduce the heat to medium low and baste the steak with the butter as it begins to brown, 2 to 3 minutes (without burning).
Transfer the steak to a rack in a roasting pan and top with a few pieces of the herbs and garlic and 3 spoonfuls of the butter. Roast to an internal temperature of 120 degrees F for medium rare, 7 to 10 minutes. Allow the meat to rest for 15 minutes before slicing.
Finish the sliced meat with a sprinkle of fleur de sel and a drizzle of aged balsamic and olive oil. Serve with the roasted shallots and a simple watercress salad if desired.
Preheat the oven to 400 degrees F.
Toss the shallots with the olive oil and thyme and season with salt and pepper. Lay the shallots on a baking sheet cut-side down. Roast until the shallots are very tender, about 25 minutes.
Toss the shallots with the vinegar and additional olive oil.