2 lb filet of beef, see notes above
1 small yellow onion, minced
4 cloves garlic, minced
2 Tbsp butter
salt and freshly cracked pepper
1 c sour cream
4 Tbsp horseradish
1. Preheat oven to 425 degrees F. Let filet of beef sit at room temperature for 20-30 minutes. Combine onion and in a small bowl. Set aside.
2. Pat tenderloins dry. Season very well with salt and freshly cracked pepper. Spread onion mixture over tenderloins.
3. Heat butter in a large oven-proof skillet over Medium-High heat. When very hot, add tenderloins and brown on both sides, about 3 minutes per side.
4. Transfer to oven and cook 15-20 minutes, until an instant-read thermometer registers 160 degrees F for Medium doneness.
5. Remove from oven and allow to rest for 5-10 minutes to reabsorb the juices. In the meantime, make horseradish cream by combining sour cream horseradish; mix well.
6. Slice filet into medallions. Serve along with horseradish cream.