Remove excess fat, chain (the tough narrow muscle running along the tenderloin), and silverskin from the beef, then cut in half crosswise to form two shorter roasts. Tie both pieces in 1 inch intervals with kitchen twine.
In a medium bowl, stir together the mustard, olive oil, garlic, herbs and pepper until smooth. Sprinkle half the salt over the beef, then slather with the mustard mixture. Place the beef in a plastic bag and refrigerate for at least 3 hours or up to overnight.
Let the beef stand at room temperature for 1 hour before you start cooking. Preheat the oven to 450°F Place a rack in a roasting pan.
Wipe excess marinade off the beef and discard. Sprinkle the remaining salt over the beef. Heat 2 tablespoons of the canola oil in a large skillet over medium high heat. Add one of the beef pieces and turn to sear on all sides until well browned. Transfer to a roasting pan and repeat with the other piece of beef.
Place the pan in the oven and roast until the internal temperature registers 125 F for medium rare, about 20 minutes. Check the beef after 15 minutes just to be sure.
Remove from the oven and transfer to a cutting board. Let rest for 15 minutes before slicing.