Huîtres à la Mornay

Ingredients

Equipment Needed

• •Sturdy oyster knife and thick folded kitchen towel
• •Small heavy saucepan, about 1.5 quarts (1.4 liters)
• •Small skillet for poaching
• •Fine-mesh sieve
• •Whisk
• •Rimmed broiler-safe tray

Instructions

1. 1

   Prepare the salt bed

   Position an oven rack 5 to 6 inches (13 to 15 cm) below the broiler. Spread the coarse salt in a rimmed, broiler-safe tray, making eight shallow hollows that will hold the shells steady. Scrub the closed oysters under cold running water and keep them cold. Leave the broiler off for now.

2. 2

   Build the Béchamel

   Melt the butter in a small heavy saucepan over medium-low heat. Stir in the flour and cook the roux, the butter-and-flour foundation, for 2 minutes without letting it color. Add about one-quarter of the warm milk and whisk until completely smooth, then add the rest in three additions. Bring the sauce to a gentle simmer and whisk for 4 to 5 minutes, until glossy and thick enough to coat the back of a spoon. If lumps appear, pull the pan from the heat and whisk firmly; if a few remain, pass the sauce through a fine sieve. Ça se rattrape.

   Gradual milk gives the roux time to absorb liquid evenly. Pour it all at once and the flour forms little sealed islands that are much harder to smooth.
3. 3

   Finish the Mornay

   Remove the Béchamel from the heat. Whisk in the Gruyère and Parmesan until melted, then season cautiously with the fine salt and white pepper. The oysters will bring their own salinity. If the Mornay tightens into a paste or looks oily, stop heating and whisk in a spoonful of the remaining warm milk until it becomes smooth again. Cover the surface directly with parchment to prevent a skin, then turn the broiler to high.

4. 4

   Shuck and clean

   Working over a bowl, open the oysters with a proper oyster knife and save every drop of their liquor. Slide the meat free without cutting it, and do not rinse it. Keep eight sound, deeply cupped bottom shells. Rinse those shells thoroughly to remove grit and fragments, dry them, and strain the oyster liquor through a fine sieve into the smallest skillet or saucepan that will hold the oysters snugly.

   Hold each oyster in a thick folded towel with the hinge exposed, and always push the knife away from your hand. A kitchen knife is too flexible and too dangerous for this work.
5. 5

   Poach the oysters

   Bring the strained oyster liquor only to its first tremble over medium heat. Add the oysters and poach for 30 to 45 seconds, turning once, until their edges just begin to curl while their centers remain plump. Lift them out immediately. Boiling is the enemy here. If they have already firmed more than intended, keep them warm and shorten the final glaze to the few seconds needed to color the sauce.

6. 6

   Fill the shells

   Nestle the eight cleaned deep shells into the salt bed. Spoon a thin layer of warm Mornay into each shell, set exactly two poached oysters on top, then cover them completely with more sauce. Divide the grated Gruyère evenly over the shells and trickle the melted butter across the cheese. Sauce below, oysters, sauce above: that order protects the shellfish from the broiler and belongs to the dish.

7. 7

   Glaze and serve

   Slide the tray beneath the fully heated broiler and watch without leaving the oven. Glaze for 60 to 90 seconds, rotating the tray if necessary, until the Mornay bubbles at the edges and the cheese takes a quick butter-gold color. Do not wait for a dark crust across every shell; the oysters would pay for it. Carry the tray straight to the table and serve instantly. À table!

Chef Tips

• •Choose medium oysters with deep, regular cups. The largest oysters become unwieldy when paired, while flat shells spill their sauce before they ever reach the broiler.
• •The broiler must be fully heated before the shells are assembled. The goal is a fast glaze that colors the Mornay while the oysters stay tender, not a slow bake that turns them firm.
• •Serve with Muscadet Sèvre-et-Maine or a mineral Chablis. Both have the acidity to clear the cheese and butter while respecting the oysters' briny character.

Advance Preparation

• •The Sauce Mornay can be made up to 4 hours ahead. Press parchment directly against its surface, chill it, then reheat over the gentlest heat and loosen with a spoonful of milk if necessary.
• •The salt bed and cleaned serving tray can be prepared several hours ahead. Scrub the oysters then, but keep them closed and cold until the sauce is ready.
• •Do not assemble the shells in advance. The sauce will loosen against the oysters, and a second heating makes their texture firm.

Frequently Asked Questions

Nutrition Information

1 serving (about 145g)