Sprinkle tenderloins with salt, pepper, and sugar; dredge in flour. Insert meat thermometer in thickest part of meat.
Melt bacon drippings in a Shallow roasting pan. Place tenderloins in pan; bake, uncovered, at 350° for 50 minutes or until thermometer registers 170°, basting occasionally.
Remove tenderloins to a serving platter, and arrange Sherried Apple Rings around meat. Spoon cooking liquid over apple rings. Slice meat and serve with apple rings.