Restaurant Recipes: Idle Rocks' Cornish Sole

"We should be using more of megrim sole,” the team at Idle Rocks boldy declares. This deep-water flat fish can be found in abundant supply in Cornish waters yet remains largely overlooked in favour of more familiar species.  Rookie error! It’s flaky, delicate in flavour and local to our waters, so we’re all in favour of chefs championing this Cornish catch.  

Served with a fragrant Thai butter, this dish is one that can be prepped almost entirely ahead of time, save for a short turn in the oven before finishing with a flash fry. Perfect for when you’re hosting or craving a light, fresh meal.

A Note on Sourcing and Preparing Megrim Sole

Sourcing megrim sole is relatively straightforward, as it's available from most good fishmongers. Top tip: always ask the fishmonger to gut, skin and trim the fish for you if you are not confident at doing this yourself. However, if you haven’t got one near you, then you can use the services of organisations like Wings of St Mawes to buy it online and have it delivered to your door.

Megrim sole doesn’t have particularly firm flesh, meaning it really benefits from being brined before use. To do this, simply make up a salt and water solution of 10% salt to water. For this, use the following:

• Add 200g table salt to 1 litre of water and bring it to the boil.
• Remove from the heat and add 1 litre or 1kg of ice. This will rapidly cool it down and give you the 10% ratio once the ice has melted.
• Make sure it is fridge-cold before using the solution.
• Once it’s cold, submerge the fish in the brine and leave it for 30 minutes. Remove and pat excess water off.

Ingredients

• 4 megrim sole, brined, prepped weight between 180-220g per fish.
• 250g unsalted butter - melted
• 2 sticks lemon grass (peeled down to core)
• 20g fish sauce
• 20g dashi powder (available online and a store cupboard must)
• 15g microplaned ginger
• 8g palm sugar
• Zest and juice of 1 lime
• 1 banana shallot, minced
• 1 red chilli, seeds out, very fine dice

Method

For the butter:

1. Warm the fish sauce up with dashi and palm sugar.
2. Mix with the melted butter, add the lemongrass and blend until smooth and pass through a chinois.
3. Add the remaining ingredients and taste. Adjust fish sauce and palm sugar as needed.
4. Using an ice tray or rubber moulds, weigh into 50g pucks and set in the fridge. 
5. Once they're completely solid, remove from their moulds and keep in a container in the fridge. The reason for doing this is that now you have pre-portioned Thai butter, meaning you only use what you need and do not waste.

To cook:

1. Preheat your oven to 180 degrees.
2. Place some parchment paper down on a tray and brush it gently with some butter or olive oil.
3. Lay your fish on top and apply some butter or olive oil, remembering not to season the fish as the brine has now done that for you.
4. Before cooking, place 4 of your butter pucks into a pan and put on a really gentle heat. You only want to melt this down slowly, being careful not to  add a lot of heat to it as this would change its flavour.
5. Place the fish in the oven and cook for between 4-6 minutes. The core temperature you are looking to achieve is 42 degrees and rising.
6. Remove from the oven and allow the fish to rest for 5 minutes.
7. Next, place the fish onto plates, then simply dress with the Thai butter over the top of the fish.
8. Serve with your desired garnish. A simple raw salad, or perhaps some salad potatoes and green beans.