Croque Madame de la Tour

Prepare the Béchamel Sauce

1. 1Melt 2 tbsp butter in a saucepan over medium heat. Whisk in the flour and cook for 1 minute, stirring constantly, until lightly golden (this is a roux).
2. 2Gradually whisk in the warmed milk until the sauce is smooth. Bring to a simmer, stirring often, until thickened.
3. 3Remove from heat and stir in the nutmeg, salt, and pepper. Set aside.

Assemble and Cook the Croque Madame

1. 1Preheat your broiler or a grill pan over medium heat.
2. 2Lightly butter one side of each slice of sourdough bread.
3. 3On the unbuttered side of two slices of bread, layer the prosciutto cotto and then top generously with grated Emmentaler cheese.
4. 4Place the remaining two slices of bread, butter-side up, on top of the cheese-and-ham layers.
5. 5Spread a layer of the béchamel sauce over the top slice of each sandwich.
6. 6Place the sandwiches under the broiler or in the grill pan. Cook until the bread is golden brown and the cheese is melted and bubbly, about 4-6 minutes per side, or until desired crispness is achieved.
7. 7While the sandwiches are cooking, fry or poach the eggs to your preference.
8. 8Carefully place a fried or poached egg on top of each Croque Madame just before serving.