Alex Guarnaschelli's Roasted Burger Topping Is A Game-Changer

Whether you are making a DIY classic Shake Shack burger in the privacy of your own kitchen or an easy smash burger, what separates one burger from the next are the toppings you use to dress them up. There are plenty of offbeat burger toppings out there, but Alex Guarnaschelli's roasted burger topping is a game-changer. During an episode of "The Kitchen," the co-host revealed that she uses a roasted mirepoix to top her burgers, creating a sweet, aromatic, delicious topping that is not among your usual suspects.

Mirepoix, a seasoning base you should always have in your freezer for your favorite soups and stew recipes, is comprised of finely chopped carrots, onions, and celery. There are generally two times more onions in the mix than carrots or celery, but Guarnaschelli uses a 1:1:1 ratio of these veggies, opting for red onions instead of the traditional white, which gives her mirepoix a balance of each veggie's flavor. 

How to make a roasted mirepoix

Guaranschelli seasons the mirepoix with salt and pepper and drizzles a little canola oil on them before popping the mix into the oven. When she roasts them, they caramelize as those natural sugars become concentrated and intensify, but there is still a slight crunch. Because she uses a high heat of 375 degrees Fahrenheit, it takes just 15 minutes to achieve. She also adds some chopped pickles, pickle juice, and a little ketchup, creating a balance of savory and sweet. The addition of the ketchup gives this a pincage vibe which is just a mirepoix with tomato paste.  

Per Food Network, Guarnaschelli explains, "This vegetable 'condiment' was introduced to me by one of [my] colleagues, Ian Halbwachs. He roasted the vegetables until they became like what you would find at the bottom of [the] roasting pan with a large cut of meat, almost candied." She further notes that when you layer this roasted mirepoix onto your grilled smashed patty, it will give your burger a "slight roast beef quality." If you like the way this roasted veggie mix tastes on your smash burger, you may want to try it on a tuna fish sandwich or a grilled cheese.