French Onion Soup Burgers with Gruyère and Arugula
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Ingredients & Equipment
What we send
- 3 ouncesbaby arugula
- 1/8 ouncethyme
- 1yellow onion
- 3 packetsunsalted butter
- 12 ouncesground beef
- 1 tablespoonflour
- 1 containerbeef stock
- 2 slicesGruyère cheese
- 2English muffins
- 2 packetsDijon mustard
What You’ll Need
- 2 10" medium pans, 1 with lid
Rinse all produce. Pat arugula dry with paper towel. Strip thyme leaves, discarding stems. Halve lemon. Peel onion, halve, and thinly slice. In a large bowl, whisk together juice of ½ lemon (or start with a little, then taste and add more as desired), ½ tablespoon olive oil, and ⅛ teaspoon salt. Set aside for Step 6. Use remaining lemon to brighten a glass of water.
Heat butter in a medium pan over medium-high heat. When butter is foamy, add thyme and onion and cook, stirring occasionally, until onion is light brown and softened, about 6 minutes. Then, add 1 tablespoon water and reduce heat to medium. Cook, stirring continuously to keep it from sticking, until onion is golden brown and very soft, about 5 minutes more.
While onion cooks, pat beef dry with paper towel and season with ½ teaspoon salt and pepper as desired. Using your hands, mix well, then form into 2 equal patties, about ½-inch thick. Using your thumb, create a dimple on top of each. Place burgers on a plate and set aside until Step 5.
Make onion gravy
Add flour to pan with onion, still over medium heat, and cook, stirring vigorously to prevent burning, until flour is no longer visible, about 2 minutes. Add beef stock and bring to a boil over high heat. Reduce heat to medium high and simmer, stirring occasionally, until gravy is thickened and reduced by ⅔, 2-3 minutes more. Remove pan from heat. Season with ⅛ teaspoon salt and pepper as desired.
Heat 1 teaspoon olive oil in a separate medium pan over medium heat. When oil is shimmering, add burgers and sear, without flipping, until browned on bottom, about 4 minutes. Flip and continue searing until browned and medium rare, 3-4 minutes. Spoon onion gravy over burgers, then top with Gruyère. Cover pan and cook until cheese is melted, 1-2 minutes more. Transfer burgers to a plate. Wipe pan clean for the next step.
Finish and plate burgers
Split English muffins open horizontally, then add cut-side down to pan from burgers over medium heat. Toast until light golden, about 2 minutes. Spread mustard over cut sides of muffins. Layer with French onion soup burgers and any remaining onion gravy. Add arugula to bowl with dressing, toss to coat, and serve with burgers. Dig in!