How to Make It
Preheat the oven to 425°. Heat a large, non-stick skillet. Working in batches, add large handfuls of spinach to the skillet and cook over moderately high heat, stirring, until wilted. Transfer to a colander and repeat with the remaining spinach. When cool enough to handle, gently squeeze out excess water and coarsely chop.
In the large, non-stick skillet, melt the butter in the oil. When hot, add the leeks and cook over moderate heat until softened, about 3 minutes. Add the garlic and cook, stirring occasionally, until softened, about 5 minutes. Add the spinach and cook, stirring, until the spinach is incorporated with the leeks and garlic. Add the heavy cream and Pernod and cook over high heat, stirring, until the cream has thickened, about 1 minute. Season with salt and pepper and let cool to room temperature.
Put the salmon filet on a large, rimmed baking sheet, skinned side down and drizzle with white wine. Season with salt and pepper and sprinkle the shallots over. Spread the spinach topping over the filet evenly. Bake in the upper third of the oven for about 15 minutes, until just cooked. Reserve at least 1 pound of the salmon and topping for the Salmon Kedgeree. Divide the remaining salmon and topping among 4 plates and serve right away.