Mix the flaky salt with ½ tsp smoked paprika and sprinkle over both sides of the cod fillets. Place them on a plate, cover with cling film and refrigerate for 1–2 hours.
Preheat the oven to fan 180°C/gas 4. Line a roasting tin with baking parchment.
Place the courgettes in the roasting tin. Add the garlic and pour on half of the fish stock. Sprinkle with the oregano and some salt and pepper. Spray with 25–30 sprays of oil. Cook on the middle shelf of the oven for 15 minutes.
Remove the fish from the fridge, wash off the salt and pat dry with kitchen paper.
Take the tray from the oven and mix through the butter beans. Nestle the fish fillets into the mixture, along with the cherry tomatoes and olives. Pour on the rest of the fish stock. Lay the chorizo slices, overlapping, on top of the cod fillets.
Sprinkle the lemon zest and juice and the remaining ½ tsp smoked paprika over everything and season with salt and pepper. Spray another 20 sprays of oil over the surface and bake in the oven for 12 minutes, until the fish is just cooked. Sprinkle with chopped parsley and serve.