Costco's Best-Kept Secret Is a Dinner Party Game-Changer (2024)

I am not a butcher. I have never broken down a side of anything larger than a Thanksgiving turkey. I have some basic skills in poultry dismemberment, and carving of large roasts and birds, but the minute a heavy cleaver or hacksaw or bandsaw are involved, I’m gonna leave that to the professionals.

However, there are certain things that carry a premium when prepped by a butcher. Rack of lamb with the bones beautifully frenched, a crown roast of pork, a tomahawk steak, a Turducken. And with the care and prep time that are a given with these items, they carry a hefty price tag. A single rack of lamb for two people can run nearly $50-60 at a decent butcher.

If you hit your butcher up for filet mignon steaks or trimmed and tied beef tenderloin roasts, you’re looking at conservatively a $32-37 per pound. Even the trimmed roasts at Costco that they have up front are $26 per pound, which is a terrific savings over the butcher shop. But the untrimmed ones in the back that they will get for you if you ask nicely? $15.79 per pound, so a $10 per pound difference over Costco prices, and less than half the cost of a butcher shop.

This whole piece of prime cow will give you, after trimming, three different cuts of meat, with about only a 10% loss of weight due to the removal of fat and silverskin, so by learning some basic techniques of breaking down this cut, it is a shockingly cost-effective way to bring home the good stuff. I started doing this when planning a party for my husband’s birthday. We were inviting a crowd for a casual backyard dinner, and a whole roasted tenderloin is always a way to take those events a bit next level for special occasions. Sliced and served with soft buns, pickled onions, horseradish sauce and some arugula, and people have a dinner that is as easy to eat as a burger, but with much less work for the host and a serious addition of fancy. But buying enough tenderloin to feed 30 people (about two large ones) could require a second mortgage.

Until I found the secret of the untrimmed tenderloin. Game. Changed.

So, here is how to get in on this magic yourself.

You will need one whole untrimmed tenderloin, if your Costco doesn’t carry them, ask your butcher, who will also have them at a much-reduced price point. You will also need a very sharp boning knife, which has a thin flexible blade, and some butchers twine or cooking twine.

Stacey Ballis

To start, the whole tenderloin has three main components. At the fatty end, there is a muscle shaped like a football which we call the chateaubriand. Essentially a mini-tenderloin, this is a perfect roast for two people, and can easily be cooked on the grill or in the oven.

Stacey Ballis

Stacey Ballis

The second is the chain, or a long string of meat surrounded by fat, and with fat marbling through it that goes nearly the full length of the cut attached to the tenderloin itself with fat and membrane. This chain is sometimes referred to as beef tips, and once trimmed and cubed, makes the best stroganoff or stew you have ever had.

Finally, you have the tenderloin itself, which has a thin pointy end, and a tubular middle section and a tapered thin flat end.

By buying the whole tenderloin, you get all of these cuts in one fell swoop. I will prep and freeze the chateaubriand and the chain meat for future bonus meals. The tenderloin itself, once trimmed and cooked, serves about 2-3 people per pound as part of a larger meal, so often anywhere from 12-16 people for a whole one. If you are looking to serve fewer guests, you can also cut them in half for a roast, and then either freeze the second half whole for a roast or cut into filet mignon steaks and freeze those for the grill.

To break down a tenderloin, start by removing the chateaubriand. Usually you can flip it over onto the underside and run your thumb along the membrane that is attaching it to the whole cut, gently separating them, and using your knife if you hit any area that feel stubborn, since you don’t want to tear the tender meat. Once you have the whole chateaubriand separated, you can use your knife to remove any pockets of fat that you see and set it aside.

The chain is also attached by a similar membrane with a line of fat between it and the larger loin muscle. Again, run your thumb along this line and gently pry the chain off of the side, which will leave you with a long section of marbled meat and fat and then the larger tenderloin. To prep the chain meat, remove any large chunks or strips of fat, and cut into one and a half inch cubes and set aside.

To start prepping the whole tenderloin, using your knife nearly flat against the meat, carefully remove any thick surface fat or membrane, being cautious not to cut into the meat. Slow and steady is the order of the day as you get used to doing this.The first time I prepped a tenderloin it took me about 45 minutes start to finish—now I can do it in about 15-20.

Stacey Ballis

Once the fat pockets have been mostly removed, you are going to want to remove the silverskin from the end, which is a flat shiny iridescent or white bit of tough sinew that will never break down in cooking and can make your roast curl up. This is pretty straightforward: Simply run the tip of your boning knife, again almost flat against the meat, between the silverskin and the meat on one end, sliding it carefully to create a little flap. Then hold this flap piece tightly with a small bit of paper toweling for traction, and with the blade facing away from you, again fairly flat against the meat, with the sharp blade tilted slightly upwards, gently slide the knife blade back and forth with long slow steady movements between the meat and the silverskin all the way to the end to remove it. You will probably have to make three to four passes to remove the whole of the silverskin, so just go slow and even.

Stacey Ballis

Stacey Ballis

Stacey Ballis

Once you have removed all the fat and silverskin from the tenderloin, you have some choices to make.

If you want filet mignon steaks, you can remove the first few inches of both tapered sides of the cut to get to the size steaks you will want, then simply create steak sections by cutting crosswise through the tenderloin the thickness you desire. The end pieces can be cut into chunks to add to your chain meat for a future stroganoff.

Stacey Ballis

To create a tenderloin roast, you will want to make the full piece as uniform as possible. To do this, cut about 10 lengths of butchers or cooking twine about 14 inches long each. On each end, fold the thinner tapered flat end over on itself about 2 inches in to double up the thickness of meat on those end pieces and tie them down to create a more uniform thickness and prevent the ends from overcooking. Then tie the roast about every inch and a half. This will keep the meat a bit taut and in a nice round shape for cooking and slicing.

Season the roast well with salt all over.

To roast, heat your oven to 250. A full tenderloin is an unwieldy wobbly thing, and it is rare that you would have a skillet large enough to sear it whole, so I always cut the tied roast in half even if I am cooking all of it. If I only need half, I vacuum seal or place the remaining roast in a zip-top bag and freeze for the next event.

In a large nonstick skillet over medium high heat, heat a tablespoon of neutral flavored oil with a high smoke point like canola or grapeseed to shimmering, then sear the roasts on all sides to a deep golden brown, about 1-2 minutes per turn. Place the seared roast(s) on a rack over a sheet pan and into your oven. Cook to an internal temperature of 120 for rare, 125 for medium rare or 130 for medium. This may take between 25-40 minutes for rare depending on the thickness of your roast, so temp it first at 20 minutes and then again every 8-10 minutes until it is done. Remove from the oven at your desired temperature, tent with foil, and let rest for 20 minutes to half an hour before slicing and serving.

For a crowd for dinner, I slice about ½ inch thick, most people will plan on 2 slices. To slice for sandwiches, I slice about ¾ of an inch thick on the presumption that people will only take one slice.

Stacey Ballis