Croque Monsieur | Mama's Cooking

Ingredients

• 2 tablespoons unsalted butter
• 3 tablespoons flour
• 2 cups milk, hot
• 1 teaspoon salt
• 1/2 teaspoon fresh ground pepper
• 1 pinch ground nutmeg
• 5 cups Gruyère cheese, grated, divided
• 1/2 cup parmesan cheese, freshly grated
• 16 slices white bread
• Dijon mustard, to taste
• 8 ounces baked ham, sliced