Crayfish Gratin Nantua
89 min · 15 steps
Hard: over 60 min or 12+ steps
About this dish
Whole live crayfish are blanched and their shells simmered into a deep coral bisque butter — the classic sauce Nantua — before the tails are folded back in and finished under the grill with a thin gratin crust that crackles without masking the sweetness of the shellfish beneath.
Allergy Info
Dairy, Gluten, Celery, Sulphites, Fish, Crustaceans
Diet Info
Pescatarian
Ingredients
Fresh Produce
- Shallotfinely minced1 medium
- Carrotfinely diced1 small
- celery stickfinely diced1
- Flat-leaf parsleyfinely chopped1 tbsp
Fish & Seafood
- Live freshwater crayfishpurged in cold salted water2 kg
Dairy & Eggs
- Unsalted butterdivided, cold and cubed90 g
- Double cream200 ml
- Gruyèrefinely grated30 g
- Parmesanfinely grated20 g
Tins & Jars
- Tomato paste2 tbsp
- Fish stockcold500 ml
Dried Goods
- Dry breadcrumbsfine1 tbsp
Spices & Seasonings
- Bouquet garnibay leaf, thyme sprig, parsley stalks1
- Cayenne pepper1 pinch
- Nutmegfreshly grated1 pinch
- Fine sea salt to taste
- White pepper to taste
Oils & Condiments
- Cognac2 tbsp
- Dry white wine150 ml
Utensils
- Large heavy saucepan
- Fine-mesh sieve
- Ice bath
- Individual gratin dishes
- Grill/broiler
- Meat thermometer
- Whisk
Method
Mince the shallot, dice the carrot and celery, grate the Gruyère and Parmesan, and combine them with the breadcrumbs in a small bowl. Set all components aside separately.
Bring a large pot of heavily salted water to a rolling boil. Drop in the live crayfish and blanch for exactly 2 minutes, then transfer immediately to an ice bath. Once cool enough to handle, twist the tails from the bodies, peel the tail meat cleanly, and devein by removing the black intestinal thread. Reserve all shells and heads.
Melt 30 g of the butter in a wide, heavy saucepan over high heat until foaming. Add the reserved shells and heads and sauté, stirring frequently, until they turn deep brick-red and smell intensely roasted, about 5–6 minutes.
Add the minced shallot, carrot, and celery to the pan and cook over medium-high heat, stirring, until the vegetables soften and begin to colour, about 3–4 minutes.
Add the tomato paste and stir constantly over medium heat until it darkens to a rust colour and loses its raw smell, about 2 minutes.
Pour in the cognac and let it bubble and reduce until the pan is almost dry, about 1 minute.
Pour in the white wine and reduce by half over medium-high heat, about 3 minutes.
Add the fish stock and bouquet garni, bring to a simmer, then cook uncovered over medium-low heat for 20 minutes.
Strain the bisque base through a fine-mesh sieve into a clean saucepan, pressing hard on the shells with the back of a ladle to extract every drop of flavour. Discard solids.
Add the double cream to the strained bisque and simmer over medium heat, stirring occasionally, until the sauce reduces to a consistency that coats the back of a spoon heavily, about 10 minutes.
Remove the sauce from the heat and whisk in the remaining 60 g cold butter a few cubes at a time until fully emulsified and glossy. Season with cayenne, nutmeg, salt, and white pepper.
Fold the peeled crayfish tails gently into the sauce and divide the mixture among four individual gratin dishes, ensuring the tails sit in a single even layer.
Scatter the cheese and breadcrumb mixture evenly over each dish.
Position the gratin dishes under a preheated grill set to its highest setting and grill until the topping is deeply golden and bubbling at the edges and the crayfish tails have reached an internal temperature of 63°C on a meat thermometer, about 4–5 minutes — watch constantly as the crust can burn quickly.
Remove from the grill, scatter with chopped parsley, and serve immediately with crusty bread.