- 1 bundle thin asparagus, trimmed into 4-inch tips (reserve stems for another use)
- 3 tablespoons butter, plus additional to cook eggs for Madame-style sandwiches
- 3 tablespoons flour
- 2 cups whole milk
- Freshly grated nutmeg
- 2 tablespoons Dijon mustard
- 8 slices good quality white Pullman bread
- 3/4 pound French-style or other thinly sliced mild wet-cured ham
- 3/4 pound Gruyère cheese, grated (about 2 cups)
- 4 large eggs
Pre-heat the oven to 400°F.
In a saucepot, bring a few inches of water to a boil. Add salt and the asparagus and cook for a couple of minutes until tender-crisp. Cold shock the asparagus in a bowl of ice water and remove them to a kitchen towel to dry.
Melt the butter in a small pot over medium heat. Add the flour, cook for a minute, then whisk in the milk. Season with salt and pepper and thicken the sauce over low bubble until very thick, 7-8 minutes. Season with a little nutmeg, turn off the heat and stir in the mustard.
Line a sheet pan with parchment paper and arrange four slices of bread on it. Top them with half of the béchamel sauce, all of the asparagus tips, all of the the ham and half of the Gruyère cheese. Set another slice of bread on each sandwich and cover them with the remaining béchamel and Gruyère. Transfer to the oven and bake for 15 minutes, until the bread is toasted on the bottom and the cheese is deep golden on top.
When the Croque Monsieurs are almost done, heat a medium nonstick skillet over medium heat with a pat of butter. Add four eggs, season with salt and pepper and cook the eggs according to your preference. (Topping the Croque Monsieurs with an egg turns them into Croque Madames). Serve with a green salad tossed with shallot vinaigrette alongside.