Sole au Gratin

Ingredients

Equipment Needed

• •Two shallow 13 x 9-inch (33 x 23 cm) ovenproof gratin dishes
• •Flexible filleting knife
• •Wide fish spatula
• •Instant-read thermometer

Instructions

1. 1

   Heat oven and mushrooms

   Set a rack in the upper third of the oven and heat it to 475°F (245°C), allowing at least twenty minutes for the oven and rack to become thoroughly hot. Butter two shallow gratin dishes with 2 tablespoons of the butter. Melt another tablespoon in a skillet, add the 16 whole mushrooms, and cook over medium-high heat for 4 to 5 minutes, until just tender and glazed and any released moisture has evaporated. Warm the finished Gratin sauce used for Gratins (No. 268) and Complete Gratin (No. 269) over gentle heat until it flows from a spoon, but do not boil it.

2. 2

   Prepare the sole

   Dry each sole thoroughly and place it with its upper, formerly dark-skinned side facing up. Run a flexible knife along the central line until it touches bone, then slide the blade outward between the bone and each of the two upper fillets. Loosen each fillet only partway, leaving its outer edge and tail end attached. Slip 1 tablespoon of softened butter beneath each upper fillet, using 8 tablespoons altogether, then season the fish lightly inside and out. The partial cut lets butter baste the flesh without allowing the sole to collapse; do not turn the fillets into loose pieces.

3. 3

   Build the gratin bed

   Divide the shallots and 2 tablespoons of the parsley between the buttered dishes. Spread 1/2 cup (120 ml) of the warm Gratin sauce associated with Gratins (No. 268) and Complete Gratin (No. 269) across the dish bottoms, using 2 tablespoons beneath each fish. Lay two soles in each dish. Place four cooked whole mushrooms alongside every sole, then distribute the sliced raw mushrooms around them. Pour 2 tablespoons of white wine around each fish, keeping it near the sauce rather than washing it over the flesh.

4. 4

   Cover and crumb

   Cover each sole evenly with 6 tablespoons of the remaining Gratin sauce for Gratins (No. 268) and Complete Gratin (No. 269). The sauce must be nappant, thick enough to coat a spoon while still flowing. If it runs like broth, reduce it alone before it touches the fish; extra crumbs will not correct a watery foundation. Sprinkle each sole with 2 tablespoons of the fine raspings, then drizzle the remaining 3 tablespoons of melted butter evenly over the crumbs. Butter, not cheese, is what binds and bronzes this crust.

5. 5

   Bake all three together

   Bake the dishes side by side for 12 to 16 minutes, checking at 10. The sole is ready when its thickest flesh reaches 145°F (63°C), looks opaque beside the central bone, and separates cleanly when nudged with a knife. At that same moment, the sauce should be bubbling and reduced at the edges, while the crumbs are deep butter-gold. If the crust browns before the fish is cooked, cover only the darkening surface loosely with foil and move the dishes one rack lower. If the fish is ready but the crust is pale, place it beneath a fully heated broiler for 30 to 60 seconds, watching without looking away. If thin sauce still pools after the fish is done, draw it carefully from the edge into a small saucepan, reduce it briskly, and return it around the sole without wetting the crust. Ça se rattrape.

6. 6

   Finish and serve

   Take the gratins from the oven and immediately scatter over the remaining parsley. Dot each sole with a few drops of lemon juice, enough to sharpen the butter and mushrooms without making the sauce taste lemony. Carry the dishes straight to the table while their edges still bubble and the crust holds firm. À table!

Chef Tips

• •Ask the fishmonger for whole portion-size sole with the central bone intact and both skins removed. Dover sole has the firmest flesh; lemon sole is an honest substitute of the same size, though a little softer. Loose fillets cook too quickly for the three parts of a complete gratin to finish together.
• •Measure the finished sauce. Too much leaves the fish cooked beneath a loose pool; too little tightens before the flesh is ready. Two tablespoons underneath and six over each portion sole give the home oven the proportion it needs.
• •Use very fine, dry bread raspings and sprinkle them lightly. A heavy blanket insulates the sauce and becomes stodgy underneath. There is no cheese here. The crust is sauce, bread, butter, and direct heat.
• •Pour a dry, mineral white such as Muscadet Sèvre et Maine or Chablis. Refrigerate leftovers within two hours and reheat them gently to 165°F (74°C), accepting that the crust will soften. This dish gives its best performance the first time.

Advance Preparation

• •The stated time assumes the finished Gratin sauce for Gratins (No. 268) and Complete Gratin (No. 269) is ready. Prepare it a day ahead, chill it promptly, and warm it gently before assembling the fish.
• •The whole mushrooms can be cooked and the raw mushrooms sliced up to four hours ahead. Keep both covered and chilled, then blot away any moisture before they enter the dishes.
• •Have the fish cleaned and skinned earlier the same day, but do not loosen the upper fillets, add the butter, or assemble the gratins until shortly before baking. Wine and salt draw moisture from the fish, while an early coating softens the crumbs.

Frequently Asked Questions

Nutrition Information

1 serving (about 370g)