Truffled potato croquettes with Dover sole

By Matt Tebbutt From Saturday Kitchen Ingredients For the croquettes 800g/1lb 12oz potatoes, peeled and cut into chunks ½ truffle, finely chopped 2 tbsp truffle oil 50g/1¾oz Parmesan, grated 2 free-range egg yolks 60g/2¼oz salted butter 100g/3½oz plain flour 2 free-range eggs, beaten …