Croque Madam

Preheat oven to 350. To make Mornay sauce: In a small saucepan, melt butter. Add flour and stir until fragrant. Gradually whisk in milk, salt, pepper, nutmeg Bring to a simmer, whisking constantly and cook until thickens Remove from heat and stir in gruyere, let cool To make sandwich: In an ovenproof skillet over medium heat, toast bread until golden on both sides Spread 1/2 tbsp butter on each slice, then flip over 2 slices and spread wach with 1 tsp mustard and 1tbsp mornay sauce Add to mustard slice 3 slices ham, 1/4 cup gruyere cheese, and remaining bread slices. Spead tops with 2 tbsp sauce, and sprinkle with remaining gruyere Transfer skillet to oven and cook 15-18 minutes, until cheese is melty and top is golden To make egg: In a nonstick skillet over medium-high heat, melt butter Crack eggs into skillet and fry until whites are set season with salt and pepper, and add to the top of each sandwich