Pork tenderloin is a great source of lean protein, and it's so easy to cook!
I got a gallon Ziploc bag, put about 3 pounds of pork tenderloin in it, and poured in a bottle of oil & vinegar - based salad dressing. I marinated it in the fridge for 22 hours, then 2 hours before I was ready to cook it, I let it sit out on the counter to get to room temperature.
After I preheated the oven to 475°, I dumped the contents out into a baking pan and arranged the tenderloins comfortably.
I let them roast for 15 minutes at 475°, then turned the oven down to 425° for another 30 minutes. At that point, I started taking the tenderloins out of the oven to check the temperature of the meat. When it registered 155° or so, I knew it was finished cooking since I like medium - medium well pork. The total oven time can be anywhere from 45 - 60 minutes.
Here it is at the dinner table, served with its own juices poured all over, with a nice escarole salad on the side. Enjoy!