Sole Mornay

Ingredients

Equipment Needed

• •2-quart (2-liter) heavy saucepan
• •Whisk and fine-mesh sieve
• •13 by 9-inch (33 by 23 cm) shallow baking dish
• •2½ to 3-quart (2.4 to 2.8-liter) broiler-safe gratin dish
• •Broad flexible fish spatula
• •Parchment paper

Instructions

1. 1

   Build the Mornay

   Melt 2 tablespoons (28 g) of the Mornay butter in a heavy saucepan over medium-low heat. Add the flour and stir for 2 minutes without letting the roux color; cooking it removes the raw flour taste while keeping the sauce ivory. Take the pan off the heat and whisk in the milk gradually, smoothing each addition before adding the next. Return it to medium-low heat, add half the cream, and cook for 5 to 7 minutes, whisking along the bottom and corners, until the sauce naps the back of a spoon and falls from the whisk in a broad ribbon. Season with half the salt and the white pepper. Remove the pan from the heat, then whisk in half the Gruyère, half the Parmesan, the remaining Mornay butter, and the remaining cream. Once the cheese enters, the sauce must not boil. If it turns grainy or shows beads of fat, pull it from the heat and whisk firmly with a spoonful of the reserved cream until smooth. Ça se rattrape. Press parchment directly against the surface and keep the Mornay warm.

   If the béchamel develops flour lumps before the cheese goes in, pass it through a fine sieve and return it to gentle heat. Straining is correction, not defeat.
2. 2

   Poach the sole gently

   Heat the oven to 325°F (165°C). Butter a 13 by 9-inch (33 by 23 cm) shallow baking dish and lay the sole fillets flat in one uncrowded layer, alternating the narrow ends so they fit without overlapping. Season with the remaining salt. Spoon the fish fumet over and around the fillets, then divide the 4 tablespoons (56 g) of poaching butter into small pieces over the fish. Lay a sheet of parchment directly against the surface and bake for 7 to 10 minutes. The fumet should barely tremble, never boil, and the fish should be opaque at the edges but only just yielding at its thickest point. If the liquid begins bubbling hard, lift the dish from the oven for a minute and lower the heat to 300°F (150°C). The broiler will finish the fish, so stop the poach early rather than late.

   The 4 tablespoons of poaching butter preserve the source entry’s half-ounce allowance for each of four sole. This butter belongs with the fish, not in the Mornay.
3. 3

   Prepare the sauce bed

   Change the oven to high broil and set a rack about 6 inches (15 cm) below the element. If the Mornay has cooled, warm it over the lowest heat only until it flows again. Spread about one-third of the sauce across the bottom of a shallow, broiler-safe gratin dish. Lift each fillet from the poaching dish with a broad fish spatula, pause to let the fumet drain away, and arrange the fish neatly over the sauce. Draining matters: excess poaching liquid thins the Mornay and prevents a clean glaze.

4. 4

   Coat with Mornay

   Spoon the remaining Mornay over the sole, covering every fillet from end to end. The sauce should cling in a generous coat rather than run like milk; if it has tightened while waiting, loosen it over gentle heat with a teaspoon of milk. Scatter the remaining Gruyère and Parmesan evenly over the surface. Do not mound the cheese heavily in the center, or the edges will brown before the middle begins to bubble.

5. 5

   Glaze under broiler

   Set the gratin dish under the hot broiler for 2 to 4 minutes, rotating it once if your heat is uneven. The Mornay should bubble at the rim and the cheeses should melt into a freckled butter-gold glaze. If one patch darkens too quickly, move the dish down a rack rather than covering the whole surface. Stop as soon as the color arrives; chasing a dark crust only overcooks the sole beneath it. The thickest fillet should be opaque and reach 145°F (63°C). Let the dish settle for 2 minutes, then carry it directly to the table. À table!

Chef Tips

• •Ask the fishmonger to skin four small sole and lift off eight even fillets. Trimming and skinning were separate brigade jobs, and handing them to the fishmonger is an honest home equivalent. If Dover sole is unavailable, lemon sole or fine flounder fillets will take the method, though thinner fillets need a shorter poach.
• •Use a light, clean fish fumet, homemade, frozen, or bought from a good fishmonger. Taste it before seasoning the sole; cheese adds salt later, and an aggressively reduced fumet can make the finished dish harsh.
• •Grate the Gruyère and Parmesan finely from the piece. Coarse strands melt unevenly, while pre-grated cheese often carries starch that makes Mornay grainy.
• •Serve Sole Mornay from its gratin dish with buttered spinach, pommes vapeur, or plain rice to catch the sauce. A mineral Chablis has enough freshness for the dairy richness without crowding the fish.
• •This dish waits poorly once glazed. Bring the guests to the table before it enters the broiler, then serve while the sauce still gleams and the sole remains tender.

Advance Preparation

• •The Mornay can be made up to one day ahead. Press parchment against its surface, chill it promptly, and reheat it over very low heat while whisking; loosen it with a spoonful of milk only if needed.
• •The cheeses may be grated and divided earlier in the day. The poaching dish can also be buttered and the gratin dish set out before guests arrive.
• •Arrange the sole in the buttered poaching dish up to 2 hours ahead, cover, and refrigerate. Add the fumet and pieces of butter only when the oven is ready. Do not poach the fish ahead, because the second heating under the broiler will make it firm.

Frequently Asked Questions

Nutrition Information

1 serving (about 320g)