This wonderful beef tenderloin (which we call lomo) pops with Latin flavors, with an avocado chimichurri that's a snap to prepare. This is a dish that will allow you to prep side dishes easily at the same time.
*Note: Resting the meat will yield juicer and more tender meat, as resting allows the juices to redistribute.
Combine all of the ingredients in a bowl and mix well to create a lovely paste. Set aside.
Combine all of the ingredients in the bowl of a food processor. Pulse until the mixture comes together, resembling a smooth-chunky salsa. Season with additional salt and pepper, to taste. Place in a bowl, cover, and place in the refrigerator.
Preheat the oven to 400 degrees.
Cut off 4 inches from the end of the tenderloin, and reserve for another use. Rub the herb mixture on the top part of the tenderloin, make sure to massage it well on the meat, covering every inch. (This is important because you want the herb crust to become one with the tenderloin.) Set aside for 20 minutes at room temperature.
Preheat a large, flat skillet or any pan large enough to sear the tenderloin. Add the olive oil to the pan and place the tenderloin crust side down. Sear for 3 minutes, season the side not touching the pan with salt and pepper, to taste, then flip over and sear for 3 minutes.
In a large roasting pan, create a bed of onions and garlic for the tenderloin. Season lightly with salt and pepper. Add the tenderloin crust side up and place in the oven for 45 minutes. Remove from the oven, transfer the tenderloin to a cutting board, and rest for 30 minutes.* Set aside the onions in a bowl and serve.