Homard à la Mornay, otherwise au Gratin

Ingredients

Equipment Needed

• •8-quart (7.5-liter) stockpot for the court-bouillon
• •2-quart (2-liter) heavy saucepan
• •Fine-mesh sieve and sturdy whisk
• •Kitchen shears, lobster crackers, and a heavy chef's knife
• •Large oval metal gratin platter or rimmed broiler-safe sheet pan

Instructions

1. 1

   Make the roux blanc

   Reserve ¼ cup (60 ml) of the milk and 2 tablespoons (30 ml) of the cream. Warm the remaining milk and cream until tiny bubbles gather at the edge, without letting it boil. Make a roux blanc (white roux): melt the 3 tablespoons of butter over medium-low heat, stir in the flour, and cook for 2 minutes while stirring constantly. Keep it pale. The flour should smell faintly of warm biscuits but take no brown color.

2. 2

   Finish the Mornay

   Whisk the warm dairy into the roux in four additions, making each one completely smooth before adding the next. Bring the sauce to the barest simmer and cook for 8 to 10 minutes, whisking often, until no raw flour taste remains. Remove it from the heat and whisk in three quarters of both cheeses, then season with the salt, white pepper, and nutmeg. The Mornay should napper, meaning it coats the back of a spoon in an even ivory film. If it is lumpy, pass it through a fine sieve. Ça se rattrape. If the cheese releases oily beads, take the pan off the heat and whisk in the reserved cold cream a teaspoon at a time; once smooth, do not boil it again.

   Grate the cheeses finely from solid pieces. Pre-grated cheese carries starches that make Mornay pasty and reluctant to melt.
3. 3

   Follow the Cardinal method

   Prepare Homard Cardinal (No. 943) exactly through the filled-shell stage, following its court-bouillon cooking, shell work, salpicon proportions, claw filling, and arrangement. At every call for Cardinal sauce, use the warm Mornay instead: use only enough to keep the sliced tail meat supple and bind the salpicon, preserving the greater part for coating. The filling should support the lobster slices, not swim beneath them. As the shells are being filled, set an oven rack 4 to 5 inches (10 to 13 cm) below the broiler and heat the broiler at its highest setting for a full 10 minutes.

4. 4

   Keep everything hot

   Hold the remaining Mornay over a saucepan of barely trembling water while the lobster is assembled, stirring occasionally and keeping the sauce between 140 and 150°F (60 and 65°C). If it tightens while waiting, warm the reserved milk and whisk it in one spoonful at a time. Do not thin the sauce until it runs; it must cling to the curved shells beneath the broiler.

5. 5

   Coat and gratinate

   Set the filled half-carapaces on a large metal gratin platter, wedging them upright with the filled claws as directed in Homard Cardinal (No. 943). Reserve 2 tablespoons of Mornay in the saucepan, then coat the lobster slices and claws generously with the rest. Mix the reserved Gruyère and Parmesan, scatter them evenly over the sauce, and trickle the melted butter across the cheese. Gratinate 4 to 5 inches (10 to 13 cm) beneath the broiler for 2 to 4 minutes, watching without interruption, until the surface is butter-gold with deeper brown freckles and the edges bubble. If it remains pale after 2 minutes, move it closer and rotate the platter rather than leaving the lobster under moderate heat. Fierce and fast is the method.

6. 6

   Rescue and serve

   Pull the platter the instant the gratin is bronzed. If butter begins separating around an edge, stop the cooking at once. Ça se rattrape: blot only the loose fat at the rim, whisk the reserved Mornay smooth, and spoon it over any broken patch without returning the platter to the broiler. Carry it directly to the table and serve one half-shell per person while the crust is still crisp at its darkest points and the lobster beneath remains tender. À table!

Chef Tips

• •The source method begins with live lobster, but you needn't dispatch it yourself. Ask the fishmonger to do this immediately before you cook, then bring the lobsters straight home and proceed without delay. Pre-cooked tails won't supply the intact shells, claw meat, or creamy carapace parts the Cardinal arrangement requires.
• •The truffle in the linked preparation is part of the salpicon, not a decorative luxury. When fresh black truffle is out of season, use a well-drained preserved black truffle from the classical pantry. Truffle oil is perfume, not a replacement.
• •Use Gruyère for supple melt and Parmesan for its drier, savory edge. Their work is shared between the Mornay and the gratin crown; piling on extra cheese makes the glaze heavy and conceals the lobster.
• •A metal platter is the safest home equivalent to the salamander service dish. Ordinary ceramic may crack beneath a fierce broiler unless its maker explicitly approves that use.
• •Serve with a plainly dressed bitter-leaf salad and bread for the sauce. A mineral Chablis, restrained white Burgundy, or dry Champagne has enough freshness for the Mornay without bullying the lobster.

Advance Preparation

• •The Mornay may be made up to one day ahead. Press buttered parchment directly against its surface, chill promptly, then reheat it slowly over barely trembling water. Restore its coating consistency with a little warm milk.
• •The court-bouillon and measured mushroom and truffle garnishes for Homard Cardinal (No. 943) may be prepared earlier the same day.
• •Do not fully assemble the shells more than 20 minutes before serving. The final gratin depends on hot lobster, hot sauce, and fierce heat arriving together; a cold center cannot be repaired by leaving delicate lobster under the broiler.

Frequently Asked Questions

Nutrition Information

1 serving (about 220g)