Ingredients

• 20g/¾oz dulse seaweed (available from specialist suppliers and some health-food shops)
• 175g/6oz butter
• softened
• ½ lemon
• juice only
• 2 fresh mackerel
• guts removed (ask your fishmonger to do this for you
• or to butterfly the mackerel for you)
• 1 shallot
• thinly sliced
• 75g/3oz broad beans (without pods
• inner membranes removed)
• 100g/3½oz fresh peas
• half removed from their pods
• half split but left in the pods
• 12 asparagus spears
• trimmed
• 4 sprigs fresh tarragon
• leaves only

Directions

• Preheat the grill to its highest setting.
• Soak the dulse seaweed in cold water for about 10 seconds
• then drain well and roughly chop. Blend in a food processor until finely chopped
• then add the softened butter and blend until well combined. Add the lemon juice and blend once more. (You can keep any you don't use in the freezer.)
• To butterfly the mackerel
• open up each mackerel belly and slide a sharp knife in under the rib cage
• flicking the bones away from the flesh. Snip the bones at the head end and tail end
• then lift out the whole rib cage and any bones. Open the mackerel out slightly
• then spoon the butter down the centre
• leaving just one large spoonful in the bowl.
• Make 2 open parcels of aluminium foil to hold the mackerel and place them onto a baking tray. Lay the butterflied mackerel inside the foil parcels and grill for 5-10 minutes
• until the butter has melted and the mackerel is just cooked through.
• Meanwhile cook the vegetables. Bring 100ml/3½fl oz water to the boil in a large frying pan. Add the shallots and broad beans and simmer for 2 minutes
• then add the peas and the pods and simmer for 1 minute. Add the asparagus spears and tarragon sprigs and return the water to a simmer. Add the last spoonful of dulse butter to the water and simmer the asparagus and vegetables for a further 2 minutes
• or until the asparagus are tender and the butter has emulsified. Season the vegetables
• to taste
• with salt and freshly ground black pepper.
• Lift the mackerel out of the aluminium trays and onto the serving plates
• drizzling any excess butter from the trays over the top. Spoon the vegetables alongside.