This burger takes the core elements of a croque monsieur — smoked ham, Gruyère, and béchamel — and builds them around an 80/20 beef patty on a toasted brioche bun. The whole thing comes together in about 50 minutes. The real reason to make it: béchamel does the job of both sauce and cheese spread, so every bite stays creamy without anything sliding out.
Before you start
The béchamel is the one technique worth getting right. Make it first, while everything else is cold, so it has time to thicken and cool slightly before assembly — a thin, hot béchamel will soak straight into the bun. Whisk constantly once the milk goes in and keep the heat at medium, not high; the sauce should coat the back of a spoon before you pull it off the heat. The second thing that matters is patty thickness. Keep each patty to about ¾ inch so the Gruyère has time to fully melt during that last minute of cooking without the beef overcooking. Press a small dimple in the center of each patty before it hits the pan — it stops the burger from puffing up into a dome.
Mistakes to avoid
- Skipping the egg entirely is actually fine here — skip it. The recipe includes an egg in the patty mix, but with 80/20 beef you already have enough fat to hold the patties together. The egg makes the texture denser and slightly spongy. Just season the beef and form the patties gently.
- Burning the butter when searing. Butter has a low smoke point. If your skillet is screaming hot before the butter goes in, it will brown and turn bitter before the patties are halfway done. Let the pan come to medium-high, add the butter, and put the patties in as soon as it stops foaming.
- Under-seasoning the béchamel. A bland béchamel makes the whole burger taste flat. Taste it after adding the nutmeg and adjust the salt before you set it aside — it should taste good on its own, not just functional.
- Using thick-cut ham. Thick ham slices bunch up and slide out of the burger. Thin-sliced deli ham folds flat against the patty and stays put through every bite.
- Not checking doneness with a thermometer. Ground beef needs to hit 160°F (71°C) internal. The 4-minutes-per-side guideline is a starting point, not a guarantee — pan temperature, patty thickness, and starting meat temperature all vary. A quick-read thermometer removes the guesswork.
French Croque Monsieur Burger
Ingredients
Béchamel Sauce
- 2 tablespoons unsalted butter
- 2 tablespoons all-purpose flour
- 1 cup whole milk preferably organic
- ¼ teaspoon nutmeg freshly grated
- 1 pinch salt to taste
- 1 pinch black pepper freshly ground
Burgers
- 500 grams ground beef 80% lean for juiciness
- 1 large egg preferably free-range
- 1 pinch salt
- 1 pinch black pepper freshly ground
- 4 slices Gruyère cheese imported for authentic flavor
- 4 slices smoked ham thinly sliced
- 4 medium brioche hamburger buns halved and lightly toasted
- 2 tablespoons butter for grilling
Instructions
- Béchamel Sauce: In a medium saucepan, melt the butter over medium heat. Stir in the flour to form a roux. Gradually whisk in the milk, and continue stirring until the mixture thickens into a smooth sauce. Add nutmeg, salt, and pepper to taste. Set aside.
- Burger Preparation: Combine the ground beef with the egg, ensuring gentle mixing to maintain tenderness. Form into four patties, seasoned with salt and pepper.
- Cooking: In a skillet over medium-high heat, melt the butter and sear the patties for about 4 minutes per side or until they reach your desired doneness. During the last minute of cooking, top each patty with a slice of Gruyère to melt.
- Assembly: Spread a tablespoon of béchamel sauce on each half of the toasted brioche buns. Layer with a slice of smoked ham, then the Gruyère-topped burger, and another slice of ham. Cap each with the other bun half.
Notes
Nutrition
FAQ
Can I make the béchamel ahead of time?
Yes — make it up to two days ahead and store it in the fridge in a sealed container. Reheat it gently in the same saucepan over low heat, whisking in a splash of milk if it has thickened too much to spread.
What can I use instead of Gruyère?
Comté is the closest swap and melts just as well. Emmental works too. Avoid pre-shredded cheeses of any kind — the anti-caking coating prevents them from melting cleanly onto the patty.
My brioche buns go soggy fast. How do I stop that?
Toast the cut sides in the same skillet after the patties come out — 60 seconds face-down in the residual butter is enough. Spread the béchamel on the bun right before assembly, not in advance.
Can I cook these on an outdoor grill instead of a skillet?
You can grill the patties, but the béchamel step still needs a saucepan, so you won’t avoid the stovetop entirely. If you do grill, use a cast-iron skillet or flat griddle insert so the butter doesn’t drip and flare up.
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