Cook macaroni until al dente. Drain and set aside.

In the same pot over medium heat, heat the butter.

Mix in the flour and whisk continuously for about one minute to form a roux, then add the cream cheese and stir to melt it.

Gradually whisk in the milk, stirring until the mixture is smooth and starts to thicken, about 3 to 5 minutes.

Stir in the cheese a little bit at a time until melted and the sauce is smooth.

Season with salt and black pepper to taste, and add another splash of milk if needed.

Add the cooked macaroni and flaked tuna to the cheese sauce. Stir until well combined and heated through.

Serve hot, garnished with fresh parsley.