2 medium waxy potatoes, such as Desiree, unpeeled
1 tbsp olive oil, plus extra for drizzling
1 large onion, sliced
2 garlic cloves, crushed
225g bag baby leaf spinach
600g salmon, tilapia or trout fillets, skinned, boned and halved lengthways
284ml double cream
1 small lemon, zest finely grated
Handful of chopped fresh dill
Handful of chopped parsley
Par-boil the potatoes for 8 minutes, then drain and set aside to cool. Dry the pan, return to a medium heat and add the oil. Add the onion and cook for 7 minutes, stirring, until softened. Add the garlic, cook for 1 minute, then add the spinach and cook, stirring, until just wilted down. Tip into a deep, 1.3-litre baking dish and spread the mixture across the base.
Preheat the oven to 220°C/gas 7. Place the salmon strips neatly in 1 layer across the spinach mixture. In a bowl, mix the cream, lemon zest and dill or parsley and season well. Pour all over the salmon, spinach and onion base.
Remove the peel from the potatoes with your fingers, and coarsely grate the potatoes directly onto the creamy salmon in a craggy layer. Drizzle with a little olive oil, season to taste and place on a baking sheet. Bake for 30 minutes, or until it’s bubbling and the potato is deep golden and crispy. Serve with steamed mangetout or green beans.