Mac and Cheese with Crispy Parmesan-Phyllo Crust

Ingredients

• Mac and Cheese
• 4 tablespoons unsalted butter
• 1 sweet onion, minced
• 3 garlic cloves, minced
• 3 tablespoons all-purpose flour
• 2½ cups whole milk
• ½ cup heavy cream
• 1 pound dry bite-size pasta, like elbow macaroni or small shells
• 2 cups shredded white cheddar cheese
• 1 cup shredded Monterey Jack cheese
• Kosher salt and freshly ground black pepper
• 1½ teaspoons smoked paprika
• 1 tablespoon Dijon mustard
• Phyllo Crust
• 16 sheets (about 14 by 18 inches each) frozen phyllo dough, thawed
• 9 tablespoons unsalted butter, melted
• Finely grated Parmesan cheese, as needed