Steam the broccoli until tender-crisp, drain thoroughly and set aside.

Boil the macaroni until tender, reserve 1 cup pasta water and drain.

Whisk milk, cornstarch and Dijon in a saucepan and simmer gently for 3 to 4 minutes until thickened.

Remove from heat and melt in white cheddar, salt and white pepper.

Fold in macaroni and broccoli and loosen with pasta water as needed.