Tasting Table / Zach Mack
To some (myself included), French onion soup is something of a culinary ideal. Whether it’s a diner, pub, or cozy bistro, digging into a cheese-encrusted crock promises an unparalleled combination of deep umami flavors, light sweetness, and instant familiarity. In my experience, one of the only ways to elevate this blissfully simple dish is to pair it alongside a perfectly cooked burger. So when Shake Shack announced it would be incorporating my go-to comfort food into its new fall menu, I was instantly desperate to have a taste.
The burger chain is slightly tweaking some of its core classics to accomplish its new French onion selections: a French onion soup burger, French onion soup ‘Shroom burger, and a French onion Shack Stack. It’s also added a pair of new sides in parmesan garlic fries and — at long last — onion rings. The seasonal items will make their big debut on September 9, 2025, exclusively on the app, before hitting all nationwide menus on September 12.
I was invited to the Shake Shack Innovation Kitchen in Manhattan’s West Village to sample these items before they hit restaurants. And from the first bite, I knew the burger chain was on to something big with its autumn offerings. Read on to see what you can expect from the seasonal menu (and why I’m officially embracing French Onion Fall).
Some recommendations are based on firsthand impressions of promotional materials and products provided by the manufacturer.
French onion soup burger
Tasting Table / Zach Mack
I personally think Shake Shack’s burger is the best one available at any fast food restaurant (even better than the In-N-Out Double-Double). In fact, when the chain was getting its start in Madison Square Park over a decade ago, I would lead the charge from my office around the corner to grab those perfectly seasoned patties smothered in Shack sauce. And while there’s practically nothing I’d change about this item, Shake Shack actually appears to have improved on a masterpiece with its French onion soup burger.
For the French onion soup burger (which has a starting price of $9.99), Shake Shack uses its ¼ pound Angus beef patty. It then tops it with melted Gruyere cheese, caramelized onions, crispy sweet onions, and a roasted garlic parmesan aioli, which is served on a toasted potato bun. Even with my hopes set sky high, I was instantly won over. The deep richness of the caramelized onions melds phenomenally with the fatty beef and cheese. A touch of sweetness provides an ideal counterbalance, while the crispy onions add a pleasantly crunchy textural component.
The underlying star element in all of this was the garlic parmesan aioli. The piquant condiment punches through the deeper, meatier flavors to provide a brighter umami point (more on that later). In fact, despite having four more items to sample, every other person at the tasting event stated they didn’t think they’d be able to hold back from finishing this whole burger.
French onion ‘shroom burger
Tasting Table / Zach Mack
The burger chain offers a vegetarian French onion option via its ‘shroom burger. A unique and delicious menu item that effectively turns fungi into a delectable delight, the French onion ‘shroom burger (starting at $10.29) includes a fried portobello mushroom cap filled with melty Muenster and cheddar cheese. This is then topped with the seasonal menu’s caramelized onions and roasted garlic parmesan aioli.
After experiencing the same flavor combinations on its beef burger, my hopes remained high that this would still work … and boy, did it ever. The additional cheeses actually brings each bite closer to feeling like you’re digging into a piping hot crock of French onion soup thanks to the inevitable cheese pull (and ooze) that accompanies it. When combined with the caramelized onions and aioli, this created a decadent symphony of umami on my tongue. The crispy portobello cap provided a similar pleasant crunch that the crispy onions brought to the non-vegetarian version.
As an avid mushroom fan, I’ve always appreciated the spongy, meaty texture provided by Shake Shack’s veggie patty. In this case, I was reminded there’s something about it that’s ever so slightly lighter on the palate (even with the added cheese filling) that allows it to really sink into your taste buds. And despite constant warnings to myself, I couldn’t keep myself from finishing this entire sample, either.
French onion Shack Stack
Tasting Table / Zach Mack
The Shack Stack has long been my go-to order from Shake Shack. Why would you want to pass up the opportunity to get both a perfectly seasoned beef patty and the iconic portobello patty in one package? Of course, given the success of the first two items, the new French onion option was all but assured to be my top pick of the chain’s seasonal group — long before my sample arrived in front of me.
True to the original iteration, this version of the Shack Stack — which is topped with the caramelized onions and roasted garlic parmesan aioli — is an especially tall sandwich. That makes taking the first bite a bit daunting; in fact, as much as I love (and reorder) this combo burger, it’s still a struggle to keep it from falling apart into your lap (which happened to a fellow taste-tester sitting next to me). Of course, this challenge is worth the extra effort: The melding of the seasoned beef patty, juicy yet crispy mushroom patty (with all its cheesy goodness), caramelized onions, and aioli leaves almost nothing to be desired in the flavor and texture departments.
Simply put, the special attention that goes into each careful bite helps you savor it even more. Perhaps unsurprisingly, it was far and away my favorite of the three seasonal burger offerings, and it’ll be available for $13.29 for customers.
Parmesan garlic fries
Tasting Table / Zach Mack
I’m a big fan of Shake Shack’s crinkle cut fries, which almost always come perfectly crisp on the outside, and nice and fluffy on the inside. Priced at $4.99, the new parmesan garlic fries are topped with a dusting of parmesan cheese, with the roasted garlic parmesan aioli on the side. Now, while my go-to dipping condiment for its fries is Shack sauce, I suggest trying this item — and its accompanying sauce — while it’s available on the fall menu.
Getting to taste this special sauce (which tastes way better than any store-bought aioli brand you may have tried) all on its own is honestly worth the purchase. Without the added bread and patty, this delicious sauce really gets to showcase how richly savory yet uplifting it is. At times, the bite of the parmesan almost gave a subtle mustard kick alongside the softly brooding yet aromatic garlic.
For me, the fresh parmesan sprinkled on top made these fries all too easy to eat, even without dipping them into the sauce. Similar to every other item that was brought out to us during the tasting (and like any good order of fries), I found myself unable to hold back from picking at this side dish until the fries were basically gone.
Onion rings
Tasting Table / Zach Mack
Stop the presses: In what could be a milestone moment for the chain, Shake Shack is finally adding onion rings to its menu — for the next few months, at least. It’s obviously appropriate that this release would coincide with a French onion soup-themed menu, though that doesn’t lessen the impact this delicious new side could have (starting at $4.49).
These are prepared with sliced Spanish onions dipped in beer batter and fried to perfection, then served with a dipping sauce of your choice. Just like the crinkle cut fries, these crisped up fantastically on the outside, but didn’t split or lose their integrity when bitten into. The onions within were perfectly soft and delicately sweet, breaking clean with each bite instead of getting degloved or slipping out of the breading.
Shake Shack offers its traditional lineup of dipping sauces alongside the rings, including BBQ, ranch, honey mustard, and Shack sauce. Frankly, each of these worked extremely well on the side, though I’m personally partial to the Shack sauce in this case. All in all, these round out what I consider to be a flawless fall menu, and I can’t wait to dig back into these items all autumn long.
Dining and Cooking