• Preheat your oven to 200°C.
• In a saucepan heat the olive oil and add the onion once the oil is hot.
• Sauté the onion till they are cooked and translucent.
• Add the fish fillets to the onions and continue to sauté for a few minutes.
• Season with the fish spice and stir well.
• Once the fish is cooked, set it aside.
• Place a large frying pan over a medium heat add half of the butter (75 g) then melt the butter in the pan.
• Add the flour to the melted butter then whisk until a smooth paste forms.
• While stirring, slowly add the cream and cook for 2 - 3 minutes or until the sauce has thickened.
• Add the mustard, peas and baby spinach to the sauce and stir well.
• Remove from the heat and allow the creamy fish to cool down for 10 - 15 minutes.

Mashed Potatoes

• Boil the diced potatoes in salted water until tender, then mash with 75 g of butter and 1 cup milk.

Assembling the fish pie

• Transfer the cooled creamy fish to a baking dish.
• Top the fish with the mashed potatoes and spread out evenly.
• Place in the oven and bake for 20 - 25 minutes or until golden in colour and the edges are bubbling.