This is a combination of a classic sauce, made famous by the Troisgros brothers, with a modern classic technique of applying confit to oily varieties of fish. My method of blending the sorrel using a home bar blender until it is smooth and green is also a modern take that I think is a dinner-party winner. Really concentrate on slow-cooking the fish; here, less is more. If salmon or ocean trout is not available, quality tuna is a suitable replacement, or Spanish mackerel.
For caper butter:
2 tsp anchovies, chopped
4 tsp lilliput (extra small) capers
1 clove garlic, chopped
½ tbsp Dijon mustard
½ tbsp tarragon, chopped
½ tbsp parsley, chopped
Few leaves basil, finely shredded
Juice of ¼ lemon
200g unsalted butter, diced and softened
Salt and pepper
For sorrel sauce:
50g unsalted butter
2 shallots, thinly sliced
15ml garlic puree
100ml Noilly Prat (or good vermouth)
300ml fish stock
2 large handfuls spinach
1 bunch sorrel
50g caper butter
For confit of salmon or ocean trout:
4 cups extra-virgin olive oil
6 x 250g salmon or ocean trout fillets
To make the caper butter, blend all ingredients in a processor until combined. Store in the refrigerator for later use — it's great with other seafood dishes.
For the sorrel sauce, melt the butter, sweat the shallots and garlic without colouring, then add Noilly Prat and reduce by half. Add the fish stock and bring to boil. Take off the heat and add the spinach to bring some colour back to the sauce.
Blend the sauce in a bar blender or with a stick blender for 2 minutes. Add the sorrel and blend for a few seconds more. Add the caper butter and blend until smooth.
Fill a heatproof dish of about 20cm square, and at least 10cm deep, with the olive oil. Put in the oven until it reaches a temperature of 70C. You will need to use a thermometer.
Add the fish and place the confit back in the oven for 10 minutes or until the fish is almost transparent.
To serve, gently reheat the sorrel sauce, then spoon on to warm plates. Remove the fish from the olive oil with a fish slice, and place each fillet in the centre of a warm plate. Accompany with a light salad.
Shannon Bennett's France: A Personal Guide to Fine Dining in Regional France, published by The Miegunyah Press, $44.99.