Halibut en Croûte with Spinach, Lemon-Herb Cream, and Fennel Butter

— The Method

How it comes together.

1. Step 01

   Start by seasoning the halibut fillets with kosher salt, black pepper, and lemon zest, then let them sit uncovered for 10 minutes so the surface dries slightly and the seasoning has time to cling. While that happens, I like to brush each fillet lightly with Dijon because it gives the fish a gentle sharpness and helps the filling grip the flesh. You want the halibut cold and firm here, not room temperature, because colder fish is easier to wrap neatly in pastry. If there is visible moisture on the fish, blot it with paper towels so the pastry stays crisp instead of steaming from underneath.

2. Step 02

   Build the filling by melting the butter in a wide sauté pan over medium heat, then cooking the shallot for about 2 minutes until it turns glossy and soft without taking color. Add the garlic and spinach and cook just until the greens collapse and most of their water cooks off, about 2 to 3 minutes more. Spread the spinach mixture on a tray or plate and let it cool completely; this matters because warm filling will soften the pastry before it ever reaches the oven. Once cooled, fold it with the cream cheese, dill, parsley, lemon juice, and smoked salt until it becomes a thick, spreadable mixture that smells bright and herbaceous.

3. Step 03

   Roll the puff pastry on a lightly floured surface until it is thin but still sturdy, then cut it into four rectangles large enough to wrap each fillet with a full border. Spoon a layer of the spinach mixture onto one side of each rectangle, set the halibut on top, and add a little more filling over the fish so every bite has moisture and flavor. Brush the pastry edges with egg yolk beaten with water, then fold and seal carefully, pressing out any trapped air pockets so the pastry bakes evenly around the fish. Set the parcels seam-side down on a parchment-lined tray and chill them for 10 minutes so the butter in the pastry firms back up.

4. Step 04

   Bake the halibut en croûte in a 400°F oven for about 22 to 26 minutes, brushing the tops with more egg wash before they go in so they bronze beautifully. I watch for a deep golden sheen and a pastry shell that feels dry and flaky when tapped; that tells me the outside is truly cooked and not just colored. Let the parcels rest for 5 minutes after baking so the fish settles and the juices redistribute instead of running out at the first cut. While they rest, melt the butter with fennel fronds and lemon juice just until fragrant, then spoon it lightly over the plate right before serving.