Preheat oven to 180 C / Gas 4. Bring a large pot of lightly salted water to the boil. Pour in pasta and cook for 8 to 10 minutes or until al dente; drain.
In large bowl, combine macaroni, soup, milk, cheese and 90g butter. Pour into 20x30cm baking dish. Top with breadcrumbs and dot with remaining butter. Bake for 45 minutes or until golden brown and bubbly.