Ingredients

Step by step

1. For the burgers, roughly chop the mackerel then pulse in a processor until finely chopped. Dice the squid into small cubes. Combine the burger ingredients (except the oil) in a bowl; cover and chill for at least 30 minutes.
2. Meanwhile make the mayo; blanch the parsley leaves in boiling water for 30 seconds, drain and refresh in iced water. Put the egg yolk in the bowl of a mini food processor; add the vinegar, mustard, a pinch of salt and the lemon juice. Slowly add the oil while the motor runs, until the mixture is thickened. Drain the parsley and pat dry on kitchen paper, chop roughly then add to the mayo and blitz until a vivid green. Transfer to a bowl, cover and chill. Preheat the oven to 180°C, fan 160°C, gas 4.
3. Trim the fennel bulb (keeping any green fronds) and shave into thin slices on a mandoline or with a sharp knife. Transfer to a bowl and toss with the lemon juice, olive oil and any finely chopped green tops. Season well.
   Tip

   This recipe contains raw eggs
4. Shape the squid mix into 4 patties. Heat 1 tablespoon of vegetable oil in a nonstick pan and fry the burgers for 1-2 minutes each side on a medium heat, until a crust forms (be careful as they may spit); transfer to a baking tray; put in the oven for 5 minutes until cooked. Insert a metal skewer in the middle of one and check it’s piping hot.
5. Add a spoonful of fennel to the toasted burger buns; add the burgers and tomato. Add a dollop of parsley mayo then the lid. Serve the rest of the mayo as a dip for chips.