2 Salmon fishcakes with melting hollandaise sauce

salmon 37.5% , alaska pollock 25.3% , potato 13.0% , fortified wheat flour 7.5% , water 7.5% , rapeseed oil 5.6% , single cream 2.8% , double cream 1.4% , potato flakes 2.0% , corn flour 0.0% , wheat flour 0.0% , unsalted butter 0.0% , onion 0.0% , spelt flakes 0.0% , barley flakes 0.0% , wheat gluten 0.0% , chives 0.0% , lemon juice 0.0% , lemon zest 0.0% , salt 0.0% , lemon juice from concentrate 0.0% , wheat germ 0.0% , fish gelatine 0.0% , white wine vinegar 0.0% , rice flour 0.0% , garlic puree 0.0% , yeast 0.0% , egg yolk powder 0.0% , white wine 0.0% , shallot 0.0% , sugar 0.0% , white pepper 0.0% , cayenne pepper 0.0% , nutmeg 0.0% , turmeric 0.0% , sunflower oil 0.0%