Éperlans au Gratin

Ingredients

Equipment Needed

• •Shallow 12 by 8-inch (30 by 20 cm) metal or broiler-safe gratin dish
• •Heavy rimmed sheet pan
• •Small skillet
• •Flexible fish spatula or broad serving spoon

Instructions

1. 1

   Heat the oven fiercely

   Set a rack in the upper third of the oven and place a heavy rimmed sheet pan on it. Heat the oven to 500°F (260°C) for at least 25 minutes, giving the sheet pan time to become thoroughly hot. Do not assemble the gratin until the oven holds its full heat. A merely warm oven cooks the smelts before it bronzes the crumbs, and no amount of patience can reverse dry fish.

   Use a shallow metal or broiler-safe gratin dish. A deep vessel insulates the sauce, while ordinary glass should not face this heat or a last-second broiler finish.
2. 2

   Prepare the mushrooms

   Separate the 8 whole mushroom caps from the sliced mushrooms. Melt 1 tablespoon of the butter in a small skillet over medium-high heat, add the caps, and cook for 3 to 4 minutes, turning once, until just tender and glossy but not deeply browned. Set them aside. Leave the sliced mushrooms raw; their moisture will mingle with the wine and reduce during the fierce oven finish, exactly as the source preparation intends.

3. 3

   Build the gratin bed

   Use 1 tablespoon of the butter to coat a shallow 12 by 8-inch (30 by 20 cm) gratin dish generously. Spread about ⅓ cup of the prepared gratin sauce over the bottom and scatter on the shallots, following the arrangement of Filets de Merlan au Gratin (No. 1018). Season the thoroughly dried smelts with the salt and white pepper, then arrange them in one close layer, alternating heads and tails so the thickness stays even. Surround the fish with the raw mushroom slices without blanketing their upper surfaces. Place the cooked caps over the dish, two to each serving, and pour ¼ cup of the wine around the edges.

4. 4

   Cover and butter

   Check the remaining gratin sauce before it touches the fish. It should fall from a spoon in a broad ribbon and veil the surface without sitting like paste; if it has tightened, loosen it with the reserved wine, one teaspoon at a time. Spoon the sauce thinly and evenly over the smelts. Scatter the bread raspings across the whole dish, melt the remaining 3 tablespoons of butter, and drizzle it evenly over the crumbs. The sauce, raspings, and butter are the complete-gratin structure described in Gratins (No. 268); keep each layer light enough that the fierce heat can reach the fish.

5. 5

   Bake in one burst

   Set the gratin dish directly on the blazing sheet pan and bake without opening the oven for the first 6 minutes. Begin checking at 7 minutes. The dish is ready when the sauce bubbles briskly around the rim, the crumbs are deeply golden, and the smelt flesh looks opaque where it meets the backbone, about 7 to 9 minutes in all. The thickest fish should reach 145°F (63°C). If the surface darkens before the fish are ready, shield it loosely with foil and give it another minute. If the fish are done while the crumbs remain pale, ça se rattrape: place the dish under a fully heated broiler for 20 to 40 seconds, watching without looking away. If the sauce remains watery once the fish are cooked, spoon the loose liquid into the mushroom skillet, boil it briefly until glossy, and return it to the dish. Do not leave little fish in the oven to correct a slow sauce.

   The tails may become crisp before the thicker bodies finish. That is welcome. Judge doneness beside the backbone, not at the delicate edges.
6. 6

   Finish and serve

   Sprinkle the parsley over the gratin and flick the lemon juice evenly across the crust. Let the dish settle for 2 minutes, no longer, so the reduced sauce gathers beneath the fish without losing its heat. Carry the gratin to the table in its baking dish and serve each person four smelts with mushrooms, crust, and a generous spoonful of sauce. À table!

Chef Tips

• •Fresh smelts should be firm and silvery, with clear eyes and a clean scent that can recall cucumber. Properly frozen smelts are an honest choice when the fresh catch is tired; thaw them overnight in the refrigerator and dry them with particular care.
• •Have the prepared gratin sauce warm before the fish are assembled. Cold sauce delays the reduction and forces the smelts to wait in the oven, which is precisely what this preparation cannot tolerate.
• •A shallow metal gratin dish is the useful home equivalent of the old fierce range equipment. The preheated sheet pan supplies hard bottom heat, while the broiler can give the final surface correction once performed under a salamander.
• •Serve with bread for the sauce and a plainly dressed bitter-leaf salad. A cold Muscadet works splendidly beside the mushrooms, white wine, and little fish; the plate needs freshness, not another rich accompaniment.
• •Éperlans au Gratin is best served at once. Refrigerate leftovers within 2 hours and eat them the following day, reheated briefly in a fierce oven, though the fish will never be quite as tender as at the first serving.

Advance Preparation

• •Prepare the referenced gratin sauce up to 1 day ahead, chill it promptly, and warm it gently before assembly. Loosen it with a little of the measured wine if chilling has made it too firm.
• •The mushroom caps may be cooked several hours ahead and kept covered in the refrigerator. Bring them out while the oven heats so they do not chill the gratin.
• •The smelts may be cleaned up to 4 hours ahead. Lay them on a rack over a tray in the refrigerator, uncovered, then dry them again immediately before seasoning.
• •Do not assemble the dish in advance. Wine and salt draw moisture from the smelts, while sauce softens the bread raspings; the gratin should go from assembly to fierce oven without waiting.

Frequently Asked Questions

Nutrition Information

1 serving (about 295g)