Preheat the oven to 400°F.

Rub the tenderloin with the oil and Emeril's Original Essence. Heat a sauté pan large enough to hold the tenderloin over high heat until the pan is very hot, about 2 minutes. Sear the meat until evenly browned on all sides, about 2 minutes per side. Remove from the heat.

Line a shallow baking pan fitted with a wire rack with aluminum foil. Place the tenderloin on the rack. Rub the top and sides of the meat with the mustard.

Combine the horseradish, black pepper, garlic, and salt in a small mixing bowl. Using your hands, press the horseradish mixture over the mustard on the top and sides of the tenderloin.  You may have to roll the tenderloin several times to make it all stick. Set it on the prepared rack.

Roast the tenderloin for about 30 minutes for rare (120 to 125°F on an instant meat thermometer) and about 35 minutes for medium-rare (130 to 140°F on an instant meat thermometer).

Remove from the oven and rest for 15 minutes before slicing.

Drizzle the beef with the Worcestershire sauce and Port Wine reduction.

*Note: Fresh horseradish roots are available at many supermarkets and some Asian markets.  Select roots that are firm, with no sign of blemishes.  After peeling, the easiest way to grate the horseradish root is to use the large-hole grater attachment on your food processor and to put it through the feed tube while you pulse.  You can also use the large-hole side of a box grater.  Either way, expect for your eyes to tear.