Preheat oven to 475°. Place tenderloin on parchment covered baking sheet and cover with a thin layer of olive oil.
Mix together all rub ingredients. Sprinkle rub generously over entire tenderloin roast, making sure to get the sides and ends. Allow the rub to adhere for 20-30 minutes.
Place in the oven for 10 minutes at 475°. After 10 minutes, reduce to 425°. Continue cooking until the thickest part reads 125° on a meat thermometer (this is typically about 20-30 minutes).
Pull out of the oven and cover in slices of butter. Cover tightly with foil and allow meat to rest and butter to melt for 10-20 minutes.
Slice about every ½", and pour melted butter and seasonings back over all the slices before serving.