My supermarket had a sale on pork tenderloin, which I don't usually buy. I picked one up and made it last night. I split the tenderloin lengthwise almost all the way through. I filled it with margarine (about one pat per person) and maple sugar. I had gotten some pure, fresh maple sugar on vacation in New Hampshire, but you could use dark brown sugar as a substitute. I put in enough sugar to make it yummy but not so much that I felt guilty. Then, I closed her up with toothpicks, counting them as I went so I would be sure to remove them all. I baked at about 375 for about 40 minutes per pound. Before serving, I poured the pan juice (which was like maple syrup) over the meat. Yummy!!!