Cook the macaroni in boiling water. Drain and set aside.

Melt 4 Tbps of the butter in a saucepan over low heat.

Stir in the flour. Cook for 5 minutes, stirring. Slowly pour in the milk, whisking consistently to prevent clumps.

Stir in the thyme, nutmeg, salt and cayenne pepper. Simmer for 10 minutes until sauce starts to thicken. Remove from heat.

Combine the sauce with the Cheddar cheese, Gruyère cheese and mustard. Cook, stirring for 3 minutes or until the cheese melts.

Crumble the LAY'S^® Salt & Vinegar Flavored Potato Chips. Combine with Parmesan cheese, breadcrumbs and remaining 4 Tbsp of butter in a large saucepan. Stir over medium heat for 5 minutes, until golden brown.

Combine the macaroni with the cheese sauce. Spoon into four bowls. Top with the potato-chip topping and enjoy!