French Onion Soup Burgers with Béchamel and Crispy Kale Chips

Imagine the rich, comforting flavors of French onion soup transformed into a hearty burger. Sweet caramelized onions, a velvety béchamel sauce and melted Gruyère cheese top perfectly seasoned beef patties, all nestled in toasted brioche buns. This recipe brings together two beloved dishes in one irresistible meal.

But that’s not all-crispy homemade kale chips add a delightful crunch on the side. They’re easy to make and a healthier alternative to fries. Whether you’re looking for a new weeknight dinner or a showstopper for your next cookout, these French onion soup burgers are sure to impress.

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Ingredients

1 unit Yellow OnionView ingredient guideLike ingredientDislike ingredient

4 ounce KaleView ingredient guideLike ingredientDislike ingredient

0.25 ounce ThymeView ingredient guideLike ingredientDislike ingredient

1 unit Beef Stock ConcentrateView ingredient guideLike ingredientDislike ingredient

0.5 cup Gruyère CheeseView ingredient guideLike ingredientDislike ingredient

1 tablespoon FlourView ingredient guideLike ingredientDislike ingredient

0.5 cup MilkView ingredient guideLike ingredientDislike ingredient

0.125 teaspoon NutmegView ingredient guideLike ingredientDislike ingredient

10 ounce Ground BeefView ingredient guideLike ingredientDislike ingredient

2 unit Brioche BunsView ingredient guideLike ingredientDislike ingredient

1 tablespoon Olive OilView ingredient guideLike ingredientDislike ingredient

1 teaspoon SugarView ingredient guideLike ingredientDislike ingredient

1 tablespoon ButterView ingredient guideLike ingredientDislike ingredient

SaltView ingredient guideLike ingredientDislike ingredient

PepperView ingredient guideLike ingredientDislike ingredient

Instructions

1. Preheat oven to 350°F. Wash and dry all produce. Halve, peel and thinly slice the onion. Remove stems and large ribs from kale, then tear leaves into bite-sized pieces. Toss kale on a baking sheet with a drizzle of olive oil and a pinch of salt and pepper. Bake until crisp, 10-12 minutes. Keep an eye on them-they can burn quickly.
2. Heat a drizzle of olive oil in a large pan over medium heat. Add sliced onion and thyme sprigs. Cook, tossing occasionally, until soft and browned, 7-8 minutes. Stir in beef stock concentrate, 1 teaspoon sugar and ¼ cup water. Simmer until onion is jammy, 2-3 minutes. Remove and discard thyme sprigs. Transfer onion to a bowl and set aside. Wipe out the pan.
3. Grate Gruyère cheese on the large holes of a grater. Melt 1 tablespoon butter in a small pot over medium heat. Add flour and stir until lightly toasted, about 1 minute. Slowly whisk in ½ cup milk, then simmer until thickened, 1-2 minutes. Season with a pinch of nutmeg, salt and pepper. Set béchamel sauce aside off heat.
4. Shape ground beef into two evenly sized patties, slightly larger than the buns. Season all over with salt and pepper. Heat a drizzle of oil in the same pan used for onion over medium-high heat. Add patties and cook until just shy of desired doneness, 3-5 minutes per side. Sprinkle cheese on top of each patty, cover the pan and cook until cheese melts, 1-2 minutes.
5. While burgers cook, split brioche buns in half and place on a baking sheet. Toast in the oven until golden, 2-3 minutes.
6. Spread béchamel sauce onto the cut sides of the buns. Fill with burgers and caramelized onions. Serve with kale chips on the side.

Recipe Tips

FAQ

Can I use a different type of cheese?

Yes, Swiss or provolone cheese are great substitutes for Gruyère.

How do I prevent kale chips from burning?

Watch them closely in the oven; they can go from perfect to burnt quickly. Check at 10 minutes and remove when crispy but not dark.

Can I make the caramelized onions ahead of time?

Absolutely. Cook the onions as directed, then refrigerate in an airtight container for up to 3 days. Reheat before assembling burgers.