Preheat the oven to 200°C, fan 180°C, gas 6. Parboil 800g of potatoes for 10 minutes, then drain and allow to cool in the colander for another 10 minutes.
Meanwhile, wrap the salmon in foil, place on a baking tray and bake for 10 minutes. Flake into a bowl and coarsely grate the cooked potato on top. Mix well and shape into 8 fishcakes.
Chop the remaining potatoes into thick wedges, then toss in 1 tablespoon oil. Lay the wedges flat on a non-stick baking tray and bake for 30 minutes, turning a few times during cooking.
Meanwhile, coat each fishcake in flour, then egg and then breadcrumbs. Place on a baking tray and brush with the remaining 2 tablespoons of oil. Cook in the oven for 25 minutes.
In the meantime, cook the peas following pack instructions and drain. Serve the fishcakes bottom-side up with the wedges and peas.
Make it veggie: Try swapping the salmon for sun-blushed tomatoes and baby spinach.