A simple blend of dried orange peel, chili powder, salt, and pepper imparts an exciting, exotic flavor to this beef. If you can't find dried orange peel in your grocery store, look at page 245 of my cookbook, Cooking From the Hip. The green sauce (see Separate Recipe), which I use all the time with fish and meat, is a unique mix of fresh parsley, oregano, and serrano and poblano chilies. If you don't like a blazing-hot amount of chilies, start with just a quarter of the poblano and the serrano, then decide whether you want to add more after tasting. You can use different peppers with this dish too: try jalapeño or whatever fresh peppers you have on hand. The sauce's flavor will be great whether you like it super-spicy or you opt to turn down the heat. I usually cook the larger cut of meat, because I love the leftovers, but whichever cut you choose, you don't have to tinker with the other ingredients, though you may want to reduce the cooking time if your tenderloin is smaller. The beef can be either grilled or pan-seared and roasted.
1. Rub the tenderloin with kosher salt and pepper to taste, then rub with the orange peel, chili powder, and sea salt. Let sit for 30 minutes.
2. Preheat the grill or, if pan-searing, preheat the oven to 450°F.
3. TO GRILL THE BEEF: Place the meat on the hot grill and sear on all sides until caramelized. Close the grill and cook, turning occasionally, 20 to 25 minutes, until an instant-read thermometer registers 125°F for medium-rare.
4. TO PAN-SEAR THE BEEF: Pour the olive oil into a large skillet over high heat. Sear the beef on all sides, about 4 minutes per side, until it is brown and caramelized. Place the beef on a rack in a roasting pan and roast for 30 to 40 minutes, or until an instant-read thermometer registers 125°F for medium-rare. Remove from the oven and let the beef rest for 20 minutes.
5. Slice the beef into 1/4-inch-thick slices and serve with the Green Sauce (See Separate Recipe).