Let the beef stand at room temperature for about 1 hour before roasting. Preheat the oven to 450 degrees.
Dice the shallots and set aside.
Pat the beef dry with a paper towel, this helps it sear in the pan which creates carmelization (aka Maillard Reaction). Rub the olive oil all over the beef, spinkle with salt and pepper on all sides.
On medium high heat, heat a large cast iron skillet, sear the beef on each side until golden brown and caramelized, and stir the shallots around in the pan. The shallots will turn dark, and that is ok, but don't let them burn, adjust your heat if necessary.
Turn off the stove, remove beef from the pan and rest on a large platter.
In the large skillet pan (don't clean it out!) add 2 cups of red wine (a good port prefered) and 3 tablespoons of butter, use a wooden spoon to scrape up all the bits known as the "fond" on the bottom of the pan. There is a lot of flavor down on the pan and you want that in your sauce! Next, add the beef back in the pan.
Carefully place the cast iron skillet into the 450 degree oven on the center rack, for 10 minutes, then flip over the beef for another 10 minutes.
The roast beef is done when internal temperature reaches medium rare 130-135 degrees, use a good accurate thermometer.
Remove from oven, rest 15 minutes, and slice thick for dinner portions and spoon the sauce over each portion, or slice thinly for roast beef sandwiches.
Serve with creamy horseradish sauce for dinner or on sandwiches.