Mac and Cheese with Ham and Mushrooms | George Ho

Ingredients

• 1 pound macaroni
• Kosher salt
• 1 pound mushrooms, roughly sliced
• 2 large onions, finely sliced
• 1 pound sliced cooked ham, cut into ½-inch cubes
• 10 tablespoons unsalted butter
• ½ cup all-purpose flour
• 4 cups evaporated milk
• Black pepper
• 2 tablespoons Dijon mustard, or more to taste
• ⅛ teaspoon cayenne pepper, or more to taste
• ½ pound sharp cheddar, grated
• ½ pound gouda, grated
• ¼ pound American cheese, thinly sliced
• ¼ pound mozzarella, cubed
• 3 scallions, biased