Rinse turkey; pat dry. Make a pocket in each tenderloin by cutting lengthwise from one side almost to, but not through, the opposite side; set aside. In a bowl combine the spinach, cheese, and black pepper. Spoon spinach mixture into pockets. Tie 100 percent cotton kitchen string around each tenderloin in 3 or 4 places to hold in stuffing.
In small bowl combine oil, paprika, salt, and cayenne; brush evenly over tenderloins. Wrap tenderlins individually in plastic wrap. Refrigerate for 4 to 24 hours.
Preheat oven to 375F. Unwrap turkey and place in a shallow roasting pan. Roast about 40 minutes or until turkey reaches 170F. Remove and discard strings; slice tenderloins crosswise.