Onion Soup Burgers perfect for Labor Day

If you’re a fan of traditional French onion soup — and who isn’t? — you’re going to love this burger. It’s kitted out with all of the ingredients that make the soup such a treasure — tender, browned onions, beef broth, red wine, Gruyere cheese and French bread — and finally lathered up with mustard mayo. Rich and full of flavor, this burger is the perfect entrée for a Labor Day bash.

Prepping it, however, does require a bit of care. The onions need to be cooked low and slow so that they’ll soften and brown properly. (You can, however, cook them a full day ahead, then cover and chill them until the moment of truth.) Likewise, you want to keep a strict eye on the burgers as they cook. Overdo it and they’ll end up dry.

You’re welcome to buy whatever kind of burger strikes your fancy, but please resist the siren call of prepackaged quarterpounders. They’re too thin for this recipe and will definitely end up overcooked. If you’re up for a little extra work, you can “grind” your own meat by buying the beef of your choice — skirt steak, short ribs, sirloin, you name it — cutting it into 1-inch cubes, freezing it for 40 minutes and finally pulsing it (in two batches) in a food processor until you reach the ground beef texture you desire.

Classic French onion soup calls for Gruyere cheese, but you’re free to swap in a different variety as long as it melts as well as Gruyere. Likewise, if you don’t want to add wine to the recipe, you can deglaze the burger pan with stock or water.

In the classic recipe, a slice of French bread is floated on the soup’s surface like a bowl-wide crouton. Here that bread provides the coziest of beds for a juicy burger. ( In truth, though, that bread — lightly brushed with olive oil, browned in the oven and rubbed with garlic — is fairly amazing all by itself.)

FRENCH ONION SOUP BURGERS INGREDIENTS

¼ cup extra-virgin olive oil, plus extra for brushing on the bread

3cups packed thinly sliced onion

Kosher salt 1teaspoon minced garlic plus 1whole clove cut in half 1teaspoon fresh thyme leaves

1⁄3 cup beef or chicken broth or water

Black pepper

Four 4-inch pieces of French bread, cut in half ¼ cup mayonnaise 1teaspoon Dijon mustard 1½ pounds ground beef, shaped into 4burgers 3ounces thinly sliced Gruyere

1⁄3 cup red wine

INSTRUCTIONS

In a large skillet heat 2 tablespoons of the oil over A French onion soup burger from a recipe by Sara Moulton. medium-high heat. Add the ing, preheat the broiler. onion and a pinch of salt, Brush the cut sides of the reduce the heat to mediumFrench bread liberally with low and cook, covered, olive oil and on a sheet pan stirring occasionally, until the broil the bread cut side up, onion is very tender, about 15 until it is golden. Remove minutes. Remove the lid and from the oven and rub the continue to cook the onion, cut sides with the cut sides uncovered, stirring frequentof the garlic clove. Transfer ly, until the onion is golden the French bread halves to brown, about 15minutes. each of 4plates. In a small Add the minced garlic and bowl stir together the maythyme and cook, stirring, 1 onnaise and the mustard minute. Add the beef broth and spread the mixture and cook, stirring the onions evenly on all the cut sides of constantly to scrape up the the bread. glaze at the bottom of the In the skillet, heat the pan, until most of the liquid remaining 2tablespoons oil has been absorbed. Transfer over high. Season the burgthe mixture to a bowl, add ers on both sides with salt salt and pepper to taste and and pepper and add them to set it aside. Clean and dry the pan. Reduce the heat to the skillet and return it to medium-high and cook the the burner. burgers until they are nicely While the onions are cook- browned (but not cooked through), about 2minutes a side.

Remove the skillet from the heat, spoon off and discard all but 1tablespoon of the fat in the pan and top each burger with one-fourth of the onion mixture and onefourth of the cheese. Pour the wine into the skillet and put it back on the burner. Reduce the heat to medium, cover the skillet and cook the burgers just until the cheese is melted, about 1 minute.

Transfer the burgers to one of the French bread halves on each of the plates. Simmer the liquid, scraping the bottom of the skillet until it is syrupy and spoon some of it over each burger. Top with the remaining French bread half and serve right away.

SARA MOULTON VIA AP