Michael Caines serves up lemon sole with Lyonnaise potatoes on Saturday Kitchen.

The ingredients for the Lyonnaise potatoes: 60g unsalted butter, ½ large onion, sliced, 1 sprig fresh thyme, leaves only, chopped, vegetable oil, for deep frying, plus 4 tsp for shallow frying, 400g floury potatoes, preferably Desiree, Maris Piper or King Edward, cut into 1cm dice, 4 tsp wholegrain mustard, 1 tbsp chopped fresh parsley and salt and freshly ground black pepper.