Croque Monsieur Panini

Name: Croque Monsieur Panini
Prep time: 15 min
Cook time: 15 min
Total time: 30 min
Yield: 2 servings
Cuisine: French
Ingredients: 1½ tablespoon (22 g) unsalted butter, cut into small pieces; 1½ tablespoon (12 g) all-purpose flour; ¾ cup (180 ml) whole milk, warmed; to taste kosher salt; to taste freshly ground black pepper; ⅛ teaspoon (½ g) freshly grated nutmeg; 4 slices brioche bread or challah, ¼-inch thick; 4 ounces (115 g) French ham (jambon de Paris) or quality deli ham, sliced thin; 3 ounces (85 g) Gruyère cheese, thinly sliced or grated; 1 tablespoon (15 ml) Dijon mustard; 1 tablespoon (15 g) unsalted butter, softened, at room temperature

From the MyKitchenBank Kitchen

A French-inspired panini combining tender ham, melted Gruyère cheese, and silky béchamel sauce griddled until crisp and golden. Sharp Dijon mustard adds a bright, tangy finish to this elegant grilled cheese sandwich.

Prep: 15 min
Cook: 15 min
Wait: 5 min
Total: 35 min
Makes: 2 panini sandwiches

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Steps

Before you start

Preheat your panini press for 5 minutes on medium heat
Make the béchamel sauce first so it cools slightly before assembly
Have all ingredients ready and measured before you begin gridding

1
Make béchamel sauce
- In a small saucepan over medium heat, melt 1.5 tablespoons (22 g) butter.
- Add 1.5 tablespoons (12 g) flour and stir constantly for 1–2 minutes until it forms a pale paste (roux).
- Slowly pour in the warmed ¾ cup (180 ml) milk while whisking continuously to prevent lumps.
- Keep whisking until the sauce thickens and coats the back of a spoon, about 3–4 minutes.
- Remove from heat.
- Season with salt, pepper, and a pinch of nutmeg.
- Set aside and let cool for 2 minutes.
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Ready when: Sauce coats the back of a spoon and is smooth with no lumps
Tip: Whisk constantly to prevent the flour from clumping. If lumps form, strain the sauce through a fine-mesh sieve.
2
Assemble sandwiches
- Place 2 bread slices on a cutting board.
- Spread a thin layer of Dijon mustard on one side of each slice, then spread a thin layer of béchamel sauce on top of the mustard.
- Layer half the ham (about 2 ounces / 57 g) and half the Gruyère cheese on one slice.
- Top with the second bread slice, mustard-and-sauce side down.
- Repeat to make a second panini.
- Spread ½ tablespoon softened butter on the outside of each sandwich (top and bottom).
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Ready when: Both sandwiches are fully assembled and buttered on all exterior surfaces
Tip: Keep béchamel and mustard thin—too much will make the sandwich soggy. Butter helps the bread crisp and brown evenly on the press.
3
Grill panini
- Place the assembled panini on the preheated panini press (medium heat).
- Close the lid gently without pressing down hard—let the press do the work.
- Grill for 4–5 minutes until the bread is golden-brown and crispy, and you hear cheese sizzling inside.
- The sandwich should feel warm and slightly compress when gently pressed.
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Ready when: Bread is deep golden-brown with light char marks, cheese is melted (visible at edges if slightly open), sandwich feels hot inside
Tip: If using a skillet instead of a press, cook for 3–4 minutes per side over medium heat, pressing gently with a spatula. Don't overcrowd or the bread browns before cheese melts.
4
Rest and serve
- Transfer the panini to a cutting board.
- Let rest for 1 minute so the cheese sets slightly and the sandwich is easier to handle.
- Cut diagonally if desired (this is traditional for a Croque Monsieur) and serve immediately while the cheese is still warm and gooey.
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Ready when: Cheese has cooled just enough that it won't ooze out when sliced
Tip: A diagonal cut looks elegant and makes the sandwich easier to eat. Serve with a small side of extra Dijon mustard or cornichons if desired.

Good to know

Tips

Make sure your panini press is properly preheated—a cold press will create soggy, pale sandwiches instead of crispy, golden ones.
Use thinly sliced ham and cheese; thick slices won't meld together properly and will create an uneven, clunky bite.
If the outside browns too quickly before the cheese melts, lower the heat slightly on your next batch or move the panini to the edges of the press where it's cooler.
For a Croque Madame variation, top the finished panini with a fried egg and let it slide over the warm cheese—pure luxury.

Make ahead

Béchamel sauce can be made up to 2 hours ahead and stored in the fridge. Reheat gently in a small saucepan over low heat, whisking occasionally, before assembling. Bread can be sliced ahead, but do not assemble the full sandwiches until you're ready to griddle.

Storage & reheating

Best enjoyed fresh immediately after grilling. Leftover panini can be wrapped in foil and stored at room temperature for up to 4 hours, or refrigerated for up to 1 day. Reheat wrapped in foil in a 325°F (163°C) oven for 8–10 minutes, or briefly on a panini press over medium heat until warmed through. Do not freeze—the bread becomes soggy when thawed.

Substitutions

Gruyère cheese → Swiss cheese or Emmental. Use the same weight; both melt beautifully and provide a similar nutty, mild flavor. Avoid pre-shredded cheese as it contains anti-caking agents.
French ham (jambon de Paris) or quality deli ham → Quality deli ham, prosciutto, or smoked ham. Jambon de Paris is traditional and gives the most authentic flavor, but any high-quality, thinly sliced ham works well. Avoid very thin-sliced packaged ham as it tears easily.
brioche bread or challah → Pain de mie or thick-cut white bread. Brioche and challah are richest; pain de mie is more neutral. Avoid sourdough or rye—their strong flavors compete with the delicate sauce.
Dijon mustard → Whole-grain or spicy brown mustard. Use the same amount. Whole-grain mustard adds texture; skip it if you prefer a smoother sauce.