This method requires either a certain level of deftness with a sharp knife or a friendly relationship with a fishmonger. Boning and stuffing the fish is something to get out of the way long before your guests appear; it’s fiddly but not too challenging. You can if you wish just stuff the cavity of the cleaned but unboned fish, though that means when it comes to eating you have to work your way around the bones as opposed to hacking straight through a cross section of meat and stuffing. Otherwise, you can take two mackerel fillets and put the stuffing in between before wrapping in bacon or prosciutto.
Preparation: 25 minutes, and 4-6 hours chilling time
Cooking Time: 1 hour
For the fish
- olive oil
- 50g/1¾oz/½ cup dried breadcrumbs
- 2 shallots, peeled and finely chopped
- 2 garlic cloves, peeled and crushed to a paste
- 1 red chilli, deseeded and finely chopped
- 10 anchovy fillets, chopped
- a big bunch of parsley, finely chopped
- 1 tsp finely chopped rosemary
- zest of 1 lemon
- salt and pepper
- 6 fresh mackerel, about 300g/10½oz each, whole and not cleaned
For the lentils
1 onion, peeled and finely chopped
1 stick of celery, finely chopped
100g/3½oz smoked streaky bacon, finely chopped
300g/10½oz/1½ cups green or Puy lentils, rinsed
600ml/20fl oz/2½ cups chicken or vegetable stock
1. Heat a little oil in a frying pan and add the breadcrumbs. Cook, stirring occasionally, until golden, then remove and set aside.
2. Add a splash more oil and gently cook the shallots until softened – about 10 minutes – then throw in the garlic, chilli, anchovies, parsley, rosemary and lemon zest.
3. Season with a good pinch of salt and plenty of pepper, and cook for a further minute or so, then mix with the breadcrumbs. Set aside to cool.
4. Using a sharp knife, chop off the heads of your fish. Now, instead of cutting along the belly as you normally would to gut a fish, carefully cut down either side of the spine to separate the flesh and the bone – make sure you don’t cut through the belly. Pull out the bones and guts and clean the fish, checking for and tweezing out any stray bones. You now have a boned and butterflied mackerel. (If you don’t feel up to this process, I’m sure a fishmonger would be happy to do it for you, but it is remarkably straightforward and surprisingly fun.)
5. Pat the fish dry and fill each cavity with the cold stuffing, then roll each fish tightly in cling film and chill for 4-6 hours, to help it hold its shape.
6. Preheat the oven to 200°C/400°F/Gas mark 6 and remove the fish from the fridge.
7. For the lentils, heat a little olive oil in a large-ish saucepan and gently cook the onion and celery until softened. Add the bacon and fry for a couple of minutes, stirring regularly, then add the lentils and stock. Bring to a boil, cover and simmer gently for 20 minutes, then take off the heat.
8. Unwrap the mackerel and put them in a roasting pan. Rub with a little oil and a good pinch of salt and roast for 15 minutes. Serve the mackerel with warm lentils and a wedge of lemon.
Recipe adapted from Do-Ahead Dinners by James Ramsden (Pavilion)