• Bring a large pan of water to the boil, then add the white potato and sweet potato. Boil for around 20 minutes until the potatoes are soft.
• Whilst the potatoes are boiling make the white sauce. In a medium pan add the butter, flour, milk and mustard powder. Over a medium heat, whisk the mixture for 3-5 minutes until it thickens (it should coat the back of a wooden spoon). Season with black pepper and set aside.
• Pre-heat the oven to 200°C/ 180°C fan/ Gas 6.
• Once the potatoes are cooked, drain and add back to the pan. Add the olive oil and roughly mash the potatoes. Set aside.
• Add the fish, prawns, peas, sweetcorn and spinach to the sauce, stir through.
• Transfer the fish mixture to a medium-sized pie dish and top with the mashed potato, spreading evenly.
• Sprinkle over the cheese and oatcakes (if using).
• Place into the oven on the middle shelf for 25-30 minutes.

Tip:

• Many of us don’t eat enough oily fish such as salmon, the recommended amount is one portion per week, as well as one portion of non oily fish such as white fish or shellfish. Oily fish are a good source of long chain omega 3 fatty acids which can help prevent heart disease.