Assuming parmesan is required, the following result was found.
slices, cut into strips 1cm/½in wide 100g/3½oz unsalted butter 150ml/5fl oz white wine 6 free-range egg yolks 50g/2oz parmesan, freshly grated, plus extra for serving 50g/2oz aged pecorino, freshly grated salt and freshly ground black pepper 350g/12oz...