Stuffed Pork Tenderloin

In a large skillet, melt butter over medium hear. Add onion and garlic; cook 5 minutes, stirring frequently, or until tender. Stir in spinach; cook 3 minutes. Add bacon, Parmesan, salt, and pepper. Stirring until cheese is melted; set aside. Butterfly tenderloin by making a lengthwise cut down center of 1 flat side, cutting to within 1/2 inch of other side. From bottom of cut, slice horizontally to 1/2 inch from left side; repeat procedure on right side. Open tenderloin, and place between 2 sheets of heavy-duty plastic wrap; flatten t 1/2 inch thickness, using a meat mallet or rolling pin.

Spread spinach mixture over tenderloin, leaving a 1/2 inch border. Roll-up tenderloin, jellyroll fashion, starting with long side. Tie tenderloin, at 2 inch intervals with heavy string. Preheat over to 475.

Place tenderloin on a lightly greased rack in a shallow roasting pan. Bake 20 minutes. Reduce heat to 325; cover, and bake 30 - 40 minutes, or until a thermometer inserted in thickest portion registers 155. Let stand 10 minutes before slicing.