Preheat the oven to 425.
Place the roast on a plate and pat dry and let it sit on the counter for 1-2 hours.
Pat the roast dry again if need. If the Beef Tenderloin has not been tied yet, tie it now.
Mix together the spices for the herb rub. (Do not mix butter and grated garlic here)
Pat the spice rub all over the roast.
Add extra virgin olive oil to a large, cast iron pan or large pan on the stove. Set heat to medium to high and heat the oil through.
Mix together slightly melted butter and the grated garlic.
Add the beef tenderloin to the hot pan and sear on three sides for about 3-5 minutes on each side. Leave the bottom unseared until the next step.
When the three other sides are done, place it on its bottom, brush the butter garlic over the top, place the chopped onions in the pan and put it in the oven.
Roast at 425 for 20-30 minutes or until a thermometer reads your desired internal temperature. Again it is recommended you remove the meat from the oven once the internal temperature in the thickest part of the meat reads 130.
Tent the beef tenderloin and rest it for 15- 20. minutes.
While resting, make the sauces for the meat. Instructions below.