Equipment
Ingredients
Base and Layers
- 15 g unsalted butter, softened
- 400 g brioche or sourdough bread, cut into 2.5 cm cubes
- 300 g thick-cut smoked ham, diced
- 200 g gruyere cheese, freshly grated
- 50 g parmesan cheese, freshly grated
Custard
- 8 large eggs
- 500 ml half and half
- 30 g dijon mustard
- 5 g kosher salt
- 2 g black pepper, freshly ground
- 1 g ground nutmeg
Nutrition (per serving)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 526 kcal
- Protein
- 28 g
- Carbohydrates
- 21 g
- Fat
- 31 g
- Fiber
- 1 g
- Sugar
- 6 g
- Sodium
- 1140 mg
- Saturated Fat
- 13 g
- Trans Fat
- 0 g
- Monounsaturated Fat
- 8 g
- Polyunsaturated Fat
- 2 g
- Cholesterol
- 252 mg
- Potassium
- 249 mg
- Calcium
- 449 mg
- Iron
- 2.7 mg
- Magnesium
- 28 mg
- Phosphorus
- 498 mg
- Zinc
- 2.4 mg
- Vitamin A
- 234 mcg
- Vitamin C
- 1 mg
- Vitamin D
- 1.2 mcg
- Vitamin E
- 0.8 mg
- Vitamin K
- 2 mcg
- Vitamin B6
- 0.2 mg
- Vitamin B12
- 1.2 mcg
- Thiamin
- 0.21 mg
- Riboflavin
- 0.48 mg
- Niacin
- 1.0 mg
- Folate
- 29 mcg
- Water
- 125 g
Sources: Aggregated Public Data, USDA FoodData Central
Method
Using a chef's knife and cutting board, cut the bread into 2.5 cm cubes and dice the smoked ham.
Grease the 33x23 cm baking dish with the softened butter. Arrange half of the bread cubes in an even layer, top with the diced ham, and add the remaining bread. Sprinkle half of the grated gruyere cheese evenly over the top.
In a large mixing bowl, thoroughly whisk together the eggs, half and half, dijon mustard, kosher salt, black pepper, and ground nutmeg until the mixture is completely homogeneous.
Pour the custard evenly over the assembled bread and ham. Press down gently on the bread so it absorbs the liquid. Cover tightly and refrigerate for at least 8 hours to allow the bread to fully hydrate.
Preheat the oven to 180°C (350°F). Remove the baking dish from the refrigerator and let it sit at room temperature while the oven heats to take the chill off the dish.
Remove the cover from the baking dish. Sprinkle the remaining gruyere and all of the parmesan cheese evenly across the top of the casserole.
Bake uncovered at 180°C (350°F) for 45 to 55 minutes, until the center is puffed and set, and the cheese has formed a bubbling, golden-brown crust. If the internal temperature is checked, it should read 74°C (165°F).
Remove from the oven and allow the strata to rest for 10 minutes before serving. This step is critical for allowing the custard to finish setting so it can be sliced neatly.
Chef's Notes
- Using slightly stale bread is absolutely crucial; fresh bread will turn into an unpleasant mush when soaked in custard. If your bread is fresh, cut it into cubes and bake at 135C (275F) for 15 minutes to dry it out.
- For the best texture and flavor, purchase block gruyere and parmesan and grate them yourself. Pre-shredded cheeses are coated with anti-caking agents that inhibit a smooth, cohesive melt.
- The dijon mustard and nutmeg are traditional croque monsieur flavor components. Do not skip them; they elevate the dish from a basic egg bake to a complex, sophisticated culinary experience.
- Do not skip the 10-minute resting period after baking. Carryover cooking completes the custard setting process, ensuring clean, beautiful slices rather than a collapsed portion.
Storage
Refrigerator: 4 days — Store tightly covered. The texture will become slightly denser over time.
Freezer: 2 months — Wrap individual portions tightly in plastic wrap, then foil, before freezing.
Reheating: Reheat individual slices in a 160C (320F) oven for 15 minutes, or microwave gently on 50 percent power until warmed through.
Troubleshooting
Casserole is soggy and watery in the center after baking
Cause: Bread was too fresh to absorb liquid, or baking time was insufficient
Fix: Cover the edges with foil to prevent burning and return to the oven for an additional 10 to 15 minutes.
Prevention: Ensure bread is stale or lightly toasted before assembling, and soak overnight.
The cheese top is burning before the custard is set
Cause: Oven temperature runs hot, or the dish is placed too high in the oven
Fix: Tent the baking dish loosely with aluminum foil for the remainder of the baking time.
Prevention: Use an oven thermometer to verify temperature and bake on the middle rack.
Cultural Context
The croque monsieur first appeared on Parisian cafe menus around 1910, celebrated for its indulgent pairing of savory ham, nutty gruyere, and rich bechamel. This casserole adaptation marries those iconic French flavors with the practical structure of an American strata, transforming a handheld bistro staple into an elegant, shared centerpiece perfect for holiday brunches.
