A few years back, at Christmas, my mother in law had a great idea for Christmas dinner. She wanted us to make a beef tenderloin roast with a layered potato dish. Justin, his brother Brian and I set to work in the kitchen. Brian took over the potatoes. Justin took charge of the meat. I made the sauce, dessert, and other goodies that night.
Since that fateful meal, Justin's creation has become a regular on our special-occasion menu. We've even tried grilling it instead of oven roasting. Both are tasty, but I'm only going to focus on the oven version here.
Now, before I get into the recipe, let me explain that there are two ways to get beef tenderloin. Obviously, if you go to the butcher and ask for a beef tenderloin, you will get beef tenderloin. However, you could get it either as the single, long tenderloin muscle all alone, or as a roast that combines some of the other muscles surrounding the tenderloin as they are found in the cow. If you shop at a normal grocery store, sometimes you have to ask the butcher and then you might get the combined roast instead of tenderloin only. We usually go to Costco and buy a humongous package of tenderloin that is whole and uncut (and usually needs the silverskin removed). We (or more exactly, Justin) will cut it up into an amount that is enough for that meal, then freeze the rest.
In the photos here, I have shown the combined tenderloin roast. It is larger around than a tenderloin alone. Just be sure to work in the olive oil, garlic, and seasonings so you don't get boring little lonely parts of cooked roast with no flavor.
2. You can use twine to tie it up neatly, or leave it loose. Place on rack in roasting pan. Put in oven.
3. After 15 minutes, reduce heat to 350F and roast for remaining time, about 30 minutes or until a meat thermometer reads 130F.
4. Remove from oven and let rest 10 minutes while covered with foil. Then slice about 3/4" thick, or to desired thickness.
5. Serve with horseradish sauce.
3. Store covered in the fridge. It stays good about 3-4 days.
PS. If you want to grill the roast, we aim for medium-hot (450-500F ish) on our gas grill. It takes about 30 minutes. Turn if it starts to char.