Croque Madame
Chapter 2 — The Mains
If you have ever sat at a white-papered table in SoHo, torn into a Croque Madame, and wondered how a simple ham and cheese sandwich could taste so profoundly rich, the secret lies in unapologetic technique. The bistro version does not cut corners. It demands high-fat cultured French butter, aged Gruyère that you grate yourself, and a proper Sauce Mornay stirred with absolute patience. This is a knife-and-fork affair where the bread is crisped in cast iron, smothered in velvety sauce, baked until violently bubbling, and crowned with an egg fried so gently the yolk remains liquid gold. It is a genuine endeavor, but this is exactly what Spring Street tastes like.
Before you start
Warm the milk.
Heat the milk gently in a small saucepan or microwave until warm to the touch, which prevents the roux from clumping when the liquid is introduced.
Grate the cheese from a block.
Pre-shredded cheese contains anti-caking agents that will ruin a smooth sauce; grate the Gruyère fresh to ensure a seamless melt.
Ingredients
- unsalted cultured French butter2 tbsp
- all-purpose flour2 tbsp
- whole milk1 1/4 cup
- egg yolk1 large
- Gruyere or Comte cheese1/2 cup
- Dijon mustard1 tsp
- nutmeg1 pinch
- kosher salt and white pepper1 pinch
- pain de mie or brioche slices4 large
- unsalted cultured French butter3 tbsp
- Dijon mustard1 tbsp
- Jambon de Paris or high-quality deli ham8 oz
- Gruyere or Comte cheese1 1/2 cup
- unsalted cultured French butter1 tbsp
- farm eggs2 large
- fleur de sel and black pepper1 pinch
- fresh chives1 tbsp
Method
- 01
Build the roux.
In a small saucepan, melt two tablespoons of butter over medium-low heat, whisk in the flour, and cook for one to two minutes until it smells nutty but takes on absolutely no color.
- 02
Whisk in the warm milk to create the béchamel.
Pour the milk in a slow, thin stream while whisking vigorously to prevent lumps, then simmer on low for five to seven minutes until it coats the back of a spoon.
- 03
Emulsify the Mornay sauce off the heat.
Remove the pan entirely from the heat to prevent the emulsion from breaking, then quickly whisk in the egg yolk, half a cup of grated Gruyère, one teaspoon of Dijon, nutmeg, salt, and white pepper.
- 04
Toast the bread in a cast-iron skillet.
Butter one side of each bread slice, place butter-side down in a medium-hot skillet, and toast for two to three minutes until deeply golden and structurally sound.
- 05
Assemble the sandwich.
Lay two slices toasted-side down, spread with the remaining Dijon, fold the ham slices over to create volume, top with a quarter cup of cheese per sandwich, and close with the remaining bread, toasted-side up.
- 06
Smother and broil.
Ladle the warm Mornay generously over the tops, pile on the remaining Gruyère, and broil for three to five minutes until the cheese is violently bubbling and leopard-spotted.
- 07
Fry the eggs to crown the dish.
While the sandwiches broil, melt one tablespoon of butter in a skillet over medium-low heat and gently fry the eggs until the whites are just set but the yolks remain entirely liquid.
- 08
Serve immediately.
Transfer the molten sandwiches to warmed plates, slide a fried egg onto each, season the yolk with fleur de sel, and finish with a scatter of minced chives.
Notes
The magic of the overnight Mornay.
The sauce fundamentally benefits from being made a day in advance to let the starches hydrate and flavors meld; simply reheat gently with a splash of cream to restore its velvety texture before building the sandwiches.
Respect the butter.
Cultured French butter has a higher fat content and lower water content than standard American butter, which is essential for achieving a clean, crisp fry on the bread without steaming it.