Preheat the oven to 375 degrees. Portion the beef tenderloin into 4 - 8 oz Filet Mignon steaks. Season both sides liberally with salt and pepper. Grill the steaks over medium-high heat for 3 minutes on each side. Transfer the steaks to a rack on a sheet pan and place in the oven for 15 minutes for a medium-rare. Place the shallots, whole peppercorns, tarragon, vinegar and white wine into a small saucepan. Heat the sauce over medium until reduced by half (approximately 5-10 minutes). Strain and discard the solids from the liquid; set aside. Melt the butter in the microwave and skim off any of the excess milk solids that rise to the top; set aside. Whip the egg yolks with a whisk over a double boiler until they thicken up (approximately 1-2 minutes). Remove from the heat. Gradually add the melted butter to the egg yolks while whisking. Once all of the butter has been incorporated, whisk in the reduced sauce and the sour cream. Season the sauce with salt and black pepper to taste. Serve each steak with a spoonful of sauce. *Option: The beef tenderloin can be seared on all sides, roasted whole, and sliced for presentation.