750g/1lb 10oz floury potatoes, cut into chunks
salt and freshly ground black pepper
50g/1ΒΎoz plain flour
25g/1oz butter
50g/1ΒΎoz strong hard cheese, such as cheddar, emmental or gruyere
2 egg yolks plus 2 whole eggs
100²µ/3Β½΄Η³ϊ panko breadcrumbs