I've seen these mackerel 'dogs' appearing at several food festivals and farmers' markets and they can be prepared in various ways – one that I tasted recently was in the form of a mackerel burger.
I've spiced a tartare sauce up a bit here with some chilli or, if you prefer, you could simply go with straight tartare sauce.
4 large mackerel fillets, boned
Flour for dusting
1 egg, beaten
40-50g fresh white breadcrumbs
Vegetable or corn oil for frying
4 large soft torpedo rolls or hot dog buns, halved
A few salad leaves (optional)
Tartare sauce, to serve, mixed with chilli sauce (or a finely chopped red chilli)
Have three bowls ready, one with the seasoned flour, one with the egg and the third with the breadcrumbs. Lightly coat the mackerel fillets in the flour, shaking off any excess, then pass through the egg and finally the breadcrumbs.
Heat the oil in a frying pan and cook the mackerel fillets for a couple of minutes on each side until crisp and golden; remove and drain on some kitchen paper. Lay a few salad leaves on the base of the hot dog bun, lay the mackerel on top with some tartare sauce and place the top on; serve immediately.