Place the pork tenderloins in a glass baking dish. Mix the remaining ingredients and pour over the tenderloins. Cover with plastic wrap and refrigerate for 8 hours or more, turning the meat several times. (If you need more marinade, add ¼ cup more cider.)

Preheat the oven to 325 degrees F. Place thin slices of lemon or apple on top of pork, if desired. Bake for 1-¼ hours or until the internal temperature of the meat reaches 160 degrees F (medium well) to 170 degrees F (well-done). While the meat bakes, baste with the marinade every 10 or 15 minutes. Let stand for 10 to 15 minutes before carving.