The Game-Changing Ingredient Angie Mar Adds To Her Burgers

Chef Angie Mar opened her New York restaurant, Le B, in September 2023 after rebranding. (The restaurant was formerly named "The Beatrice Inn.") After the change, one iconic dish remained on the menu: her 45-day dry-aged burger. The restaurant sells them for $38 each — they're actually one of America's most expensive burgers. Mar's dish stands out from many of the basic patties you can order elsewhere. The ingredient that takes her burgers to new heights? Caramelized red wine onions.

In a YouTube video, one food influencer went into further detail about the onions, calling them "really, really sweet, but not over the top." The content creator also noted that they "balance out really well" both from the wine used during caramelization and with the addition of creamy d'Affinois cheese. The acidity of the onions contrasts and complements the hearty beef patty, according to a Reel on Instagram. The condiment also pairs well with the eggy richness of the brioche bun.

Angie Mar previously shared her recipe for the caramelized onions with The Mercury News. When it comes to choosing the right wine, she suggests using a cabernet, though any red will be sufficient — so long as the quality of the wine isn't bad. She begins by pre-cooking white onions until soft. Then, the wine is added to continue the caramelization process.

According to the caption if the Instagram Reel, the caramelization process is slow. It takes Mar about 8 hours to achieve the quality she desires for the condiment. Fortunately, a larger batch of onions can be prepared at once — the chef claims they'll stay fresh in the fridge for up to five days.

As the onions caramelize and the red wine reduces, the veggies will take on the deep flavors of the fermented fruit to become slightly sweet. Texturally, the onions may feel a little jammy. When using them as a burger topping, though, this may be beneficial for keeping them together under the bun. Additionally, the color of the wine will tint the onions, too, which take on an almost burgundy hue.

In addition to the deeply flavored onions, Angie Mar has a very particular way of preparing the beef patty for her burgers. Firstly, she uses mostly cuts of 90% lean ribeye meat. On Instagram, Mar explains that it "is a really good cut. [It] is something that you would want on your plate for dinner. So why not have it as a burger, right?"

That meat is then formed into 8-ounce patties and dry-aged for around six weeks. The aging process could make the meat lose some of its moisture, which will in turn create a slightly more tender texture once cooked. Mar says the process creates "a really intense beef flavor" by concentrating the flavors. 

For those who want to try Le B's burger, you'll need to be one of the earlier diners at the bar: The restaurant serves just nine of them each day. But if you're not a New York native (or visiting the Big Apple), try caramelizing your onions in red wine the next time you grill up some burgers. You might just find the sweet, acidic flavor to be the perfect accompaniment to the richness of the beef.