- Preheat the oven to 180 °C (350 °F).
- In a shallow pan, soften the leeks in the butter for 5 minutes, without browning them.
- Add the spinach and white wine. Cook until the spinach has wilted.
- Add the broth, cream, and potatoes. Stir to combine. Season with nutmeg, salt and pepper.
- Cover and bake for 30 to 40 minutes.
- Remove from the oven and place the fish on the potatoes. Season with salt and pepper.
- Continue baking, uncovered, for 15 to 20 minutes.
- Sprinkle with the parsley and serve.