Eitan Bernath's Croque Monsieur Tuna Melt Recipe - Exclusive

This is not a case of "If it ain't broke, don't fix it." Eitan Bernath knows that you know how to make a tuna sandwich. If Julia Child's tuna and mayo habit didn't inspire you, maybe Ina Garten's anchovy paste-infused tuna melts did. And if not, Vice President Kamala Harris gave us all a tutorial in 2020. But Bernath — whose debut cookbook, "Eitan Eats the World," came out earlier this year — is nothing if not a comfort food connoisseur.

Bernath's version of a tuna sandwich is shamelessly "bougie" (his words, not ours) but also bewitching. To make the croque monsieur tuna melt, you'll combine mustard, shallots, and cornichons to make a brasserie-worthy tuna salad, then top it with nutty Gruyère. As if that weren't enough, the whole thing gets smothered in creamy béchamel sauce. It's a tuna melt that reflects Bernath himself: a little bit quirky, not pompous but bordering on baroque, and just generally extraordinary.

Recipe reprinted with permission from "Eitan Eats the World." Copyright © 2022 by Eitan Bernath. Photography Copyright © 2022 by Mark Weinberg. Published by Clarkson Potter Publishers, an imprint of Penguin Random House.

Eitan Bernath's Croque Monsieur Tuna Melt Recipe - Exclusive
5 from 25 ratings
Eitan Bernath's first cookbook, "Eitan Eats the World," is out now, and here is his delicious recipe for the Croque Monsieur Tuna Melt.
Prep Time
Cook Time
croque monsieur tuna melt on plate
Total time: 17 minutes
  • For the tuna salad
  • 3 (6-ounce) cans solid white tuna packed in water, drained
  • ⅓ cup mayonnaise
  • 2 tablespoons Dijon mustard
  • 2 tablespoons lemon juice
  • 1 teaspoon dried dill
  • ¼ cup finely chopped shallot
  • ¼ cup finely chopped celery
  • ¼ cup finely chopped cornichons
  • kosher salt and freshly ground black pepper
  • For the mornay sauce
  • 2 tablespoons unsalted butter
  • 2 tablespoons all-purpose flour
  • 1 ½ cups whole milk
  • ½ cup grated Gruyère cheese
  • kosher salt and freshly ground black pepper
  • Assembly
  • 8 (½-inch-thick) slices bread, such as sourdough, toasted
  • Dijon mustard, to taste
  • 1 ¼ cups grated Gruyère cheese
  1. Preheat the oven to 400 F and place a rack in the upper third.
  2. Place the tuna in a colander or fine-mesh sieve. Using the back of a wooden spoon or large serving spoon, press out any excess moisture, ensuring the tuna is as dry as possible. Set aside.
  3. To assemble the tuna salad, place the mayonnaise, mustard, lemon juice, and dill in a large bowl and whisk to combine. Add the shallot, celery, and cornichons to the bowl and whisk again to combine. Add the tuna and use a large spoon to stir until just mixed. Taste and season with salt and pepper and set aside.
  4. Start the mornay sauce. In a medium saucepan over medium heat, melt the butter. Once the butter is fully melted, sprinkle the flour evenly over it and, whisking vigorously, cook until it smells nutty, 1 to 2 minutes.
  5. Slowly pour in the milk, whisking constantly to prevent lumps. Cook, stirring constantly, until the sauce thickens, 3 to 5 minutes. (If the mixture climbs above a simmer, reduce the heat to medium-low.) The sauce should coat the back of a wooden spoon, and a clean line should hold when you drag a finger across it.
  6. Remove from the heat and whisk in the Gruyère until fully incorporated. Stir in the salt and pepper to taste, then set aside until ready to use.
  7. To assemble the sandwiches, arrange 4 slices of toasted bread on a sheet pan and spread mustard on top. Divide the tuna salad among the 4 slices, then top each with ¼ cup of the grated Gruyère. Place the remaining toasts on top, then pour the sauce evenly over the sandwiches.
  8. Sprinkle the remaining ¼ cup grated Gruyère over the sandwiches, place them in the oven, and bake for 5 minutes. Turn the oven to low broil and broil until the cheese is melted and the sauce is bubbling and browned, 2 to 3 minutes more.
  9. Let cool slightly before cutting each sandwich in half. Serve immediately.
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