Chef Paul Watters shared a recipe for fish pie topped with sweet potato mash and melted cheese as a St Patrick's Day special.

The dish serves four. It calls for 400g white fish such as cod or haddock in chunks, 150g salmon in chunks, and 100g prawns. Other ingredients include a small diced onion, minced garlic clove, butter, olive oil, plain flour, milk, Dijon mustard, chopped fresh dill or parsley, and frozen peas.

The sweet potato topping uses two large peeled and chopped sweet potatoes, butter, milk or cream, salt, pepper, and 100-120g grated cheddar cheese.

To prepare, boil the sweet potatoes in salted water for 15 minutes until soft. Drain and mash with butter, milk, salt, and pepper.

For the filling, heat butter and olive oil. Cook onion for 4-5 minutes until soft, add garlic for one minute, stir in flour for one minute, then whisk in milk to thicken. Add mustard, herbs, peas, salt, pepper, fish, and prawns. Cook for 2-3 minutes.

Assemble in a baking dish, spread mash on top, add cheese. Bake at 190°C for 20-25 minutes until golden and bubbling.

Serve with steamed broccoli florets, sliced carrots, and cauliflower florets, seasoned with salt and optional butter.