Preheat oven to 400 °F (200 °C).

Cook macaroni al dente according to package directions. Drain and set aside.

Meanwhile, in a large saucepan, melt butter over medium heat.

Gradually add flour, whisking constantly. Cook for 1 minute. Gradually whisk in milk until smooth. Continue whisking while bringing to a boil. Simmer for 5 minutes or until thickened. Add salt, pepper and cayenne pepper and whisk.

Remove from heat and add 2 cups (500 mL) cheese, chives and egg yolk, stirring between each addition.

Add drained pasta and mix well.

Brush a baking dish with canola oil. Pour in macaroni and cheese, top with remaining cheese and sprinkle with Panko breadcrumbs.

Bake for 15 minutes or until cheese is golden brown and bubbly. Let stand for 10 minutes. Serve with steamed vegetables.