Classic French Croque Madame with Creamy Mornay Sauce Tips, FAQ & printable recipe

Tips for success

To achieve the best results, use freshly grated Gruyère rather than pre-shredded cheese. Pre-shredded varieties are often coated in anti-caking agents like cellulose, which can prevent the cheese from melting into the smooth, creamy consistency required for a proper Mornay sauce.

Grating it yourself ensures a superior, uniform melt every time you prepare this classic French dish.

If you prefer a more intense flavor, add a tiny dash of Dijon mustard directly into the Mornay sauce as you whisk it. This adds a subtle tang that cuts through the richness of the cheese and butter.

Alternatively, you can garnish the finished sandwich with a sprinkle of fresh chives or a tiny pinch of cracked black pepper to add a pop of color and freshness.

Variations

• Croque Monsieur: Omit the fried egg entirely to create a classic Croque Monsieur. This version focuses solely on the delicious combination of ham, Gruyère, and the rich, cheesy Mornay sauce crust.
• Herbed Mornay: Stir one teaspoon of finely chopped fresh thyme or chives into the Mornay sauce. The addition of fresh herbs brings a bright, aromatic quality that pairs beautifully with the nutty Gruyère.

Storage and make-ahead

Fridge

Store in an airtight container in the refrigerator for up to 24 hours.

Reheat

Reheat in a preheated oven at 350°F (175°C) until warmed through; avoid the microwave to keep the bread from becoming soggy.

If you have leftovers, allow them to cool completely before placing them in an airtight container. Keep the sandwich and the egg separate if possible to maintain the texture of the bread.

Store in the refrigerator for up to one day. Note that the texture of the brioche will change upon storage, so consuming it fresh is always recommended for the best experience.

You can prepare the Mornay sauce a few hours in advance and store it in the refrigerator. When ready to serve, gently reheat the sauce over low heat, adding a splash of milk if it has thickened too much. Assemble the sandwich and broil it just before serving to ensure the bread stays crisp and the cheese is perfectly melted and hot.

Serving ideas

Serve the Croque Madame immediately while it is hot from the oven and the egg is fresh from the pan. This dish is designed to be eaten with a knife and fork, as the combination of the runny yolk and the creamy sauce makes it quite decadent. A simple side salad with a light vinaigrette provides a refreshing contrast to the richness of the sandwich.

Present the sandwich on a warm plate to help maintain its temperature throughout the meal. A bistro-style setting works perfectly, perhaps with a side of lightly dressed mixed greens or some cornichons.

The contrast between the warm, cheesy sandwich and a crisp, cold salad makes for a balanced and satisfying brunch experience that is sure to delight anyone at your table.

Frequently asked questions

Recipe card

Classic French Croque Madame with Creamy Mornay Sauce

Prep 5 minCook 10 minTotal 15 minServes 1

Ingredients

• 20 g unsalted butter
• 20 g all-purpose flour
• 200 ml whole milk, warmed
• to taste ground nutmeg
• 40 g Gruyère cheese, shredded
• 2 slices brioche bread
• 1 tsp Dijon mustard
• 80 g deli ham
• 50 g Gruyère cheese, shredded
• 1 large egg
• 1 tsp butter for frying

Instructions

1. In a small saucepan over medium heat, melt the butter. Whisk in the flour and cook for one minute to create a roux. Gradually whisk in the warm milk until smooth. Stir in the nutmeg and 40 grams of shredded Gruyère until the cheese has melted into a velvety, thick Mornay sauce.
2. Spread Dijon mustard on the brioche slices. Layer the ham between the slices. Pour the Mornay sauce generously over the top of the sandwich. Sprinkle with the remaining 50 grams of Gruyère. Place under a broiler set to 450°F (230°C) for 4 minutes until the cheese is bubbling and golden brown.
3. While the sandwich broils, melt the remaining butter in a non-stick pan over medium heat. Crack the egg into the pan and fry until the whites are set and the yolk reaches 160°F (71°C) for safety, keeping the yolk runny if desired. Place the fried egg atop the hot sandwich and serve immediately.

Contains: gluten, eggs, milk, mustard

Food safety: This recipe includes a sunny-side up egg which is not fully cooked. Consuming raw or undercooked eggs may increase risk of foodborne illness.

Estimated nutrition per serving

Calories

580

Protein

24.5 g

Carbohydrates

32 g

Fat

38 g

Fiber

1.5 g

Sugar

6 g

Sodium

950 mg

Automatic estimate from the ingredient list, not laboratory-verified.