Truffle Baked Macaroni and Cheese

Ingredients

• 8 ounces elbow macaroni
• 6 tablespoons butter
• 3 tablespoons flour
• 3 1/2 cups milk
• 1/2 white onion medium
• 1 bay leaf
• 1 teaspoon kosher salt
• 1 teaspoon black pepper
• 1 pinch cayenne pepper
• 3 tablespoons black truffles finely chopped
• 10 ounces white cheddar sharp aged, grated
• 3 ounces gruyere grated
• 1 ounce Parmesan cheese grated
• 2 drops black truffle oil
• 1 cup breadcrumbs brioche
• 2 tablespoons parsley chopped
• black truffles sliced, to garnish, optional