Wash the rocket in a bowl of cold water - try to avoid running the tap over the leaves as this will break the leaves and turn them brown.
Cut the halibut into small pieces. Place in a bowl and squeeze the juice of 1 lemon and 1 orange over them. Add a drizzle of olive oil and the white balsamic. Mix with a spoon until the fish changes slightly in colour and texture. Season to taste.
Remove leaves from the coriander and finely chop with a sharp knife.
Use a sharp knife to remove all the skin and white pith from the remaining orange and lemon. Remove the segments and squeeze the juice from the remaining flesh.
For the fennel slaw: thinly slice the fennel on a mandolin, season with salt and pepper, olive oil and the lemon juice. Mix well.
To serve: place a few rocket leaves on a plate and place a stainless steel serving ring on top. Fill the pastry ring with the marinated halibut, pressing it down firmly. Remove the ring and arrange the citrus segments around the fish. Drizzle the citrus juice over the dish and sprinkle the coriander leaves on top.
«Be careful not to over-marinate the fish as this could cause it to become chewy.»