Preheat oven to 400℉.
Lay the chile peppers on a baking sheet and put into the oven to roast for about 20 minutes. Long enough for the peppers to start to char and soften.
Remove from the oven and let cool long enough so that you can handle them. Remove as much of the blistered pepper skin as you can. You should be able to peel it off with your fingers.
Remove the stem and seeds. Place the peppers in the bowl of a food processor or blender.
To the bowl, also add the rest of the marinade ingredients.
Pulse until the peppers are finely chopped and the ingredients are combined.
Cut the tenderloin(s) into 1-inch slices and lay in a baking dish with the slices next to each other.
Spoon the marinade between each pork slice and on top of the tenderloin.
Cover and refrigerate several hours or overnight.
Preheat the oven to 450℉.
When ready to bake, either remove the tenderloins to a new baking dish or if using the same dish that the meat was marinating in, remove as much of the liquid in the bottom of the pan that you would like to (or you can leave it in).
Bake uncovered for 10 minutes at 450℉.
Turn oven temperature to 325℉ and bake for approximately 30-40 minutes longer (145° for medium rare and 160° for medium).
Loosely tent the pan with foil and let the pork sit for about 3 minutes.
Serve on a bed of rice or shredded lettuce with radishes, limes, salsa, avocado, sour cream or any of your favorite garnishes.