A fried egg crowns this decadent sandwich of ham enrobed in béchamel and melted cheese from Oklahoma City's Ludivine restaurant.
6 tbsp. unsalted butter
4 tbsp. flour
1 cup milk
5½ tbsp. Dijon mustard
¼ tsp. freshly grated nutmeg
Kosher salt and freshly ground black pepper
8 slices country bread, toasted
8 oz. thinly sliced smoked ham
16 oz. Gruyère cheese
Crème fraîche, for garnish
Mixed green salad, for serving (optional)
1. Melt 4 tbsp. butter in a 2-qt. saucepan over medium-high heat. Whisk in flour; cook 2 minutes. Whisk in milk; bring to a boil. Reduce heat to medium-low; cook until slightly thick, making a béchamel sauce, 6–8 minutes. Whisk in 1 ½ tbsp. mustard, plus nutmeg, salt, and pepper; set sauce aside.
2. Heat broiler to high. Place 4 slices bread on a baking sheet and spread 1 tbsp. mustard over each. Top each with 2 oz. ham, 2 tbsp. béchamel sauce, and 2 oz. cheese. Broil until cheese begins to melt, 1–2 minutes. Top with remaining bread slices and spread with remaining sauce; sprinkle with remaining cheese. Broil until cheese is browned and bubbly, 3–4 minutes.
3. Meanwhile, melt remaining butter in a 12" nonstick skillet over medium heat. Add eggs and season with salt and pepper; cook until whites are cooked but yolks are still runny, about 3 minutes. Place an egg on top of each sandwich, garnish with a dollop of crème fraîche. Serve with salad.