The Burger Lab: The Fake Shack, Mach Two—The Double Shack Stack Cracked

A little over a year ago, I deconstructed and reconstructed a Shake Shack burger at home and have been enjoying the brown-crusted, beefy, juicy, gooey, and flavorful results on a regular basis ever since (without having to wait in line, that is). The Shack burger was the original burger-that-changed-my-life, and for the record, it's still just as good as it's ever been (at least at the Madison Square Park location—more on that in a few days).

However, in the immortal words of the Dude, some new sh*t has come to light, namely: The Double Shack Stack.

You see, I've made a new years resolution to start consuming more calories in order to compensate for the extra exercise that my wife has for some reason compelled me into resolving to do as well. Rather than eat more burgers (that would just be gluttonous), I've decided just to pack more into each one.

Robyn's the one who originally turned me on to the Double Shack Stack, and I think she can much more aptly explain the glories of this cheese-bomb, so allow me to excerpt her previous entry on the subject:

Crispy deep-fried breaded portobello mushrooms. Tender juice-oozing meat patties. Gooey blanket of cheese. All in the same glorious bite. It's an umami explosion that left my friend and me speechless, aside from the countless times we said, "HOLY CRAP, THIS IS SO GOOD, OH MY GOD."

Although I'd usually be against a burger whose height cannot be completely contained by the average person's mouth, this is an exception. It's not about balance. It's about combining varying textures—crispiness with meatiness with gooeyness—and dousing it in varying fats—mostly of the dairy and bovine sort—and then shoving it in your mouth however you can, and subsequently feeling like the happiest person in the world.

Indeed it is glorious, all 1,130 calories of it. And this week, we're going to figure out how to make one at home.

The Base

To begin with, we've already got a good deal of this sandwich licked. After all, the bun, sauce, meat, cheese slices, and toppings are exactly the same as the traditional Double Shackburger. For those of you who missed the original breakdown, here's a quick recap:

The bun is a Martin's Sandwich-sized potato roll, hinge kept intact, toasted in melted butter on a griddle. The patty is a custom Pat LaFrieda blend (one of the first!), consisting of a 50:25:25 blend of sirloin, chuck, and brisket. The sirloin provides a textural backbone, the chuck fat and beefiness, and the brisket its signature high, slightly metallic flavor. It's a tasty combo.

The patties are seasoned with salt and pepper then smashed down onto a stainless steel cooking surface. A minute later, they get scraped off with a stiff spatula for maximum crust formation. After flipping, they get a single slice of gooey yellow American cheese on top. The toppings are a couple slices of ripe roma tomato, a single token leaf of greenleaf lettuce, and a smear of Shack sauce, essentially a blended mix of mayo, ketchup, mustard, dill pickles, and a few spices (cayenne, paprika, garlic powder).

Where the Double Shack Stack veers towards extra-awesomeness is with the addition of a 'Shroom Burger. Two portobello mushroom cups sandwich around big glob of cheese that gets breaded in panko-style breadcrumbs and deep fried until golden brown, crisp, and gooey.

Sounds like a piece of cake, right? Well I quickly learned that attempting to hold back a lava-flow of molten cheese is not quite as simple as it looks.

Consume the 'Shroom

First off, I followed my normal protocol: interview and dissection. By talking to the incredibly friendly and helpful floor manager at the Upper East Side location (why can't all fast food employees be as happy and friendly as Shacksters?), I learned that the 'Shroom Burgers for every shake shack are made in the same off-site commissary, which is good news—it meant that whatever store you go to, you'll get the exact same product. As to the specifics of manufacture, she couldn't divulge much more than the fact that they are made with portobello mushrooms, they are stuffed with muenster and cheddar, and the breading contains eggs.

Back home, a few more details emerged. Each 3-ounce post-cook-weight puck contains 2 ounces of cheese, the portobello caps are pressed to a remarkable thin size, and each one is 3-inches in diameter. With those parameters in mind, I constructed my first prototype patty using two 3-inch mushroom caps, an ounce each of grated cheddar and muenster, and a standard flour-egg-panko breading. Admittedly, the Shroom burger was far too large and wonky, but I fried it anyway.

The results were a disaster. The mushrooms exude a ton of liquid as they cook which in turn evaporates, causing massive blowout and a pot full of broken cheese curds matched only by my broken dreams. Obviously, some form of pre-cooking was required.

I tried both roasting in the oven and sautéing on the stovetop with plain mushrooms, and mushrooms coated with a thin layer of olive oil. The plain mushrooms didn't work, period: The outer skin dries out into an inedible leathery sheath. The slicked up mushrooms, fared much better initially, but when it came time to coat them, the coating had a tendency to slip off, making complete enclosure impossible. And if there's one thing these patties need, it's complete enclosure.

What about some moist cooking methods? Boiling worked alright, but the 'shrooms came out frustratingly waterlogged. Much better was a stint in my bamboo steamer. After 10 minutes of steaming they were fully tender, after which I pressed them between a couple layers of paper towels to remove excess moisture. I also discovered an important fact here: the mushrooms lost about 25% of their diameter during cooking. Caps that started out 4-inches wide ended up a perfect 3-inches post-cook.

Even better, I found that I could get nearly identical results in the microwave by layering the mushrooms between two heavy plates lined with paper towels and cooking them for three to four minutes. Man, do I love low frequency electro-magnetic radiation.

Get Stuffed

Next up: the cheese. After a couple brief experiments with slabs and carefully-constructed ovoid carvings that fit precisely in my portobello shell, I realized that by far the simplest and most effective way to shape the cheese was to simply grate it and pack it the same way I'd pack a burger patty, albeit with a firmer hand. With that method, the two types of cheese blend together (muenster provided gooeyness and cheddar for a bit of sharp kick) and conform exactly to the shape of the portobello.

Twisting the whole thing up in a sheet of plastic wrap helped to tighten the whole thing into a compact and cohesive package, which I subsequently breaded and tried to fry.

No good. Another premature cheesesplosion. Melted muenster geysered into my wok, causing oil to splatter all over the counter and leaving me with an empty shell of portobello caps, albeit a very crisp one.

The solution came from a technique I used to use back on the garde-manger station at Clio, where we offered a breaded and deep-fried cube of melty camembert as part of a cheese course: double-dipping. After the standard flour/egg/breadcrumb dip, I put the shrooms back in for another bath in the eggs followed by one last coat of breadcrumbs. Letting the patties rest in the crumbs for a few minutes until the egg began to dry out also ensured proper adhesion during frying.

With my technique in order, all that remained was to fry up a few samples at the office for an official tasting.

And how were they? I think Robyn, once again, says it best: