Croque Madame With Creamy Sauce and Runny Fried Egg

Quick Recipe Version (TL;DR)

• Yield: 2 sandwiches (2 servings)
• Prep Time: 15 minutes
• Cook Time: 20 minutes
• Total Time: 35 minutes

Quick Ingredients

• 2 tbsp (28 g) unsalted butter, divided
• 1 tbsp (8 g) all-purpose flour
• 3/4 cup (180 ml) whole milk
• 1/8 tsp ground nutmeg
• 1/2 tsp kosher salt, plus more to taste
• 1/4 tsp black pepper, plus more to taste
• 1 tsp Dijon mustard
• 1 cup (100 g) grated Gruyère cheese, divided
• 4 slices sturdy white sandwich bread (about 1/2 inch / 1.3 cm thick)
• 8 oz (225 g) deli ham, thinly sliced
• 2 large eggs

Do This

• 1) Make a quick Mornay sauce: melt 1 tbsp butter, whisk in flour 1 minute, whisk in milk; simmer 2–3 minutes until thick.
• 2) Season sauce with nutmeg, salt, pepper, Dijon; melt in 1/2 cup Gruyère.
• 3) Toast bread lightly; build 2 sandwiches with ham and a little Gruyère inside.
• 4) Spread a thick layer of sauce on top of each sandwich; sprinkle with remaining Gruyère.
• 5) Broil on a sheet pan 2–4 minutes until bubbly and browned in spots.
• 6) Fry 2 eggs in 1 tbsp butter, 2–3 minutes until whites set and yolks are just runny.
• 7) Top each sandwich with a fried egg; finish with black pepper and serve hot.

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Why You’ll Love This Recipe

• Classic bistro comfort: melty ham-and-cheese with a rich, creamy sauce.
• Perfect contrast: crisp edges, soft center, and that runny yolk on top.
• Home-cook friendly: no fancy equipment—just a skillet and broiler.
• Fast but impressive: ready in about 35 minutes, brunch- or dinner-worthy.

Grocery List

• Produce: optional chopped parsley (for garnish)
• Dairy: unsalted butter, whole milk, Gruyère cheese, eggs
• Pantry: all-purpose flour, kosher salt, black pepper, ground nutmeg, Dijon mustard, sturdy white sandwich bread
• Meat/Deli: deli ham (thinly sliced)

Full Ingredients

For the Creamy Sauce (Quick Mornay)

• 1 tbsp (14 g) unsalted butter
• 1 tbsp (8 g) all-purpose flour
• 3/4 cup (180 ml) whole milk, warmed (microwave 30–45 seconds)
• 1/2 tsp kosher salt
• 1/4 tsp black pepper
• 1/8 tsp ground nutmeg
• 1 tsp Dijon mustard
• 1/2 cup (50 g) grated Gruyère cheese

For the Sandwiches

• 4 slices sturdy white sandwich bread (about 1/2 inch / 1.3 cm thick; brioche or pain de mie works well)
• 8 oz (225 g) deli ham, thinly sliced
• 1/2 cup (50 g) grated Gruyère cheese (for inside and on top)

For the Fried Eggs (Croque Madame Finish)

• 1 tbsp (14 g) unsalted butter
• 2 large eggs
• Pinch of kosher salt
• Pinch of black pepper

Optional Garnish

• 1 tbsp chopped parsley
• Extra cracked black pepper

Step-by-Step Instructions

Step 1: Preheat the broiler and set up your pan

Move an oven rack to about 6 inches (15 cm) below the broiler. Preheat the broiler to High (typically 500°F / 260°C).

Line a sheet pan with foil for easy cleanup. Have your grated Gruyère ready—once the sauce is done, things move quickly.

Step 2: Make a smooth, creamy Mornay sauce

In a small saucepan over medium heat, melt 1 tbsp (14 g) butter. Whisk in 1 tbsp (8 g) flour and cook, whisking constantly, for 1 minute (this cooks out the raw flour taste).

Slowly whisk in the 3/4 cup (180 ml) warmed milk. Keep whisking until the mixture is smooth, then bring to a gentle simmer. Cook for 2–3 minutes, whisking frequently, until thick enough to coat the back of a spoon.

Step 3: Season and enrich the sauce with cheese

Remove the saucepan from the heat. Whisk in 1/2 tsp kosher salt, 1/4 tsp black pepper, 1/8 tsp nutmeg, and 1 tsp Dijon mustard.

Stir in 1/2 cup (50 g) grated Gruyère until fully melted and glossy. Taste and adjust salt/pepper if needed. The sauce should be thick and spoonable—thick enough to sit on top of the sandwich rather than run off.

Step 4: Toast the bread lightly and build the sandwiches

Lightly toast the bread so it has just a bit of structure (this helps it stay crisp under the sauce). You can toast in a toaster or in a dry skillet over medium heat, about 1–2 minutes per side.

Build two sandwiches: place ham on two slices of bread (divide 8 oz / 225 g evenly). Sprinkle a little of the remaining 1/2 cup (50 g) Gruyère inside each sandwich, then close with the other bread slices.

Step 5: Sauce the tops and broil until bubbling

Place the sandwiches on the prepared sheet pan. Spoon the Mornay sauce generously over the top of each sandwich (use it all), spreading it close to the edges.

Sprinkle the remaining Gruyère over the sauce.

Broil on High for 2–4 minutes, watching closely, until the top is bubbly and browned in spots. (Broilers vary; pull them the moment the cheese turns deeply golden to avoid burning.)

Step 6: Fry the eggs until the yolks are just runny

While the sandwiches broil (or immediately after), heat a nonstick skillet over medium-low to medium heat. Add 1 tbsp (14 g) butter and let it melt and foam.

Crack in 2 eggs. Season with a small pinch of salt and pepper. Cook for 2–3 minutes, until the whites are fully set but the yolks are still soft and jiggly. If you need help setting the tops of the whites, add 1 tsp water to the pan and cover for 20–30 seconds—keep it brief so the yolks stay runny.

Step 7: Assemble, finish, and serve hot

Transfer each broiled sandwich to a plate. Gently place one fried egg on top of each.

Finish with extra cracked black pepper and optional chopped parsley. Serve immediately while the sauce is hot, the cheese is stretchy, and the egg yolk is just runny.

Pro Tips

• Warm the milk: adding warm milk to the roux helps the sauce thicken faster and stay smooth.
• Keep the sauce thick: a loose sauce slides off; simmer until it’s truly spoonable and coats the back of a spoon.
• Toast the bread first: a quick toast adds structure and helps prevent sogginess under the sauce.
• Broiler vigilance: broilers can go from golden to burnt fast—stay nearby and rotate the pan if needed.
• Runny yolk timing: cook eggs on medium-low to medium heat for better control; pull them when the yolk still wobbles.

Variations

• Croque Monsieur: skip the fried egg and serve as-is with the bubbly cheese sauce topping.
• Extra-savory topping: add 2 tbsp (20 g) finely grated Parmesan to the sauce along with the Gruyère for a sharper bite.
• Mustard-forward: spread 1/2 tsp Dijon mustard inside each sandwich before adding ham.

Storage & Make-Ahead

This dish is best eaten right away. If you need to prep ahead, you can make the sauce up to 2 days in advance and refrigerate it in an airtight container. Reheat gently over low heat, whisking in 1–2 tbsp milk (15–30 ml) to loosen until spoonable again.

Leftover assembled sandwiches can be refrigerated for up to 2 days, but the bread will soften. Reheat on a sheet pan in a 375°F / 190°C oven for 10–12 minutes, then broil briefly (about 30–60 seconds) to re-crisp the top. Fry fresh eggs just before serving.

Nutrition (per serving)

Approximate, per 1 topped sandwich: 820 calories, 44 g protein, 48 g fat, 50 g carbohydrates, 3 g fiber, 9 g sugar, 1900 mg sodium.