(Photo courtesy of CheryllShubert)
The sauce in this recipe calls for a roux, a mixture of melted butter or oil and flour that is stirred over medium-low heat and used to thicken mixtures. Liquid is gradually whisked into the roux, and the mixture is cooked until thickened. In most cases, a roux is cooked for just 2 to 3 minutes to cook off the raw flour taste and is not allowed to color, but roux used in Cajun and Creole gumbos is cooked to a range of colors, from golden to dark brown in order to add depth of flavor.
- 6 tablespoons unsalted butter, plus more for greasing
- 1/4 cup all-purpose flour
- 2 cups milk
- 1 teaspoon sea salt, plus more, to taste
- Freshly ground white pepper, to taste
- 1 pound spinach, stemmed and well washed but not dried
- 4 (6-ounce) sole fillets
- 1/2 pound cooked cocktail shrimp
- 1/2 cup chicken stock or low-sodium chicken broth
- 1 tablespoon tomato paste
- Pinch of cayenne pepper, or to taste
- Minced fresh chives for garnish
Preheat an oven to 375°F. Lightly butter an 8-by-12-inch gratin dish.
In a saucepan over medium-low heat, melt the butter. Stir in the flour to make a roux and cook, stirring constantly, for 2 to 3 minutes; do not let the mixture color. Gradually whisk in the milk. Increase the heat to medium and bring the mixture to a simmer, whisking frequently. Adjust the heat to maintain a low simmer and cook, whisking frequently, until thickened into a white sauce, about 10 minutes. Whisk in the 1 teaspoon salt and white pepper to taste. Cover and set aside.
Place the spinach in a small stockpot and set over medium heat. Cover and cook until wilted, about 3 minutes. Empty into a colander and run cold water over the spinach to cool. In small handfuls, squeeze as much water from the spinach as possible. Using a chef’s knife, chop the spinach finely. Transfer to a bowl and stir in 1/2 cup of the white sauce; season with salt and pepper.
Lay the sole fillets, smooth skin side down, on a cutting board. Check the fish for bones, removing and discarding any you find. Spoon 1/4 of the spinach mixture onto the center of each fillet, and fold the 2 ends of the fillet over the top of the spinach. Using a metal spatula, transfer each fillet, seam side down, to the prepared dish.
In a blender, combine all but 1/4 cup of the shrimp, the remaining white sauce, the stock and the tomato paste and puree until smooth. Transfer to a bowl and season with salt and cayenne.
Pour the sauce over the sole and bake until the fish is opaque throughout, about 25 minutes. Sprinkle the remaining shrimp on top of the fish and bake for 5 minutes more. Sprinkle with chives and serve immediately.
Adapted from Williams-Sonoma Collection Series, Seafood, by Carolyn Miller (Simon & Schuster, 2005).