Smoked eel sandwich with onion pickle

Begin by preparing the onion pickle. Combine the sugar and vinegar together in a pan and gently warm until dissolved. Remove from the heat and add the sliced onion to the pan, setting aside to steep for 1 hour

For the sandwich, place a griddle pan over a medium heat to warm up. Once hot, add the sourdough slice to the pan and grill on one side until brown. While the bread is toasting, slice the eel fillet into 3 even pieces

Remove the toasted sourdough, keeping the pan on the heat, and generously spread the toasted side of the bread first with butter followed by a little Dijon mustard. Slice the bread in half and top one half with the eel pieces followed by the horseradish cream. Place the other half on top (toasted side down) and return the sandwich to the griddle pan

Grill the sandwich on one side until brown, then flip carefully and grill for a further few minutes until golden and toasted. Drain the pickle and spoon onto a plate, adding the sandwich alongside it. Serve immediately