300g/10½oz dried pasta, such as farfalle
salt and freshly ground black pepper
3 tbsp dried breadcrumbs
50g/1¾oz plain flour
freshly grated nutmeg
120g/4½oz unsalted butter, plus extra for greasing
250g/9oz Gruyère, grated
750ml/1¼ pint full-fat milk
75²µ/2½´Ç³ú Parmesan, grated
250g/9oz smoked salmon, cut into strips