Lightly sweat the shallot with the butter, without colouring, then add to the mash, flaked hot-smoked salmon, herbs, lemon zest and juice, and season, if required. Let the mixture cool, then cover and chill in the refrigerator.
Preheat the oven to 180°C/gas mark 4. Put the flour, beaten eggs and breadcrumbs to coat the fingers in three separate bowls. Mould the smoked salmon mixture into approximately 6 cm × 2 cm × 2 cm lengths. Pass the fish fingers first through the flour, then the egg, then the breadcrumbs. Repeat the egg and breadcrumb coatings for a second time to ensure a good coating. Keep in the refrigerator until ready to cook. Shallow-fry the fish fingers until golden brown and finish in the oven until hot through. This takes just a few minutes.
To make the dressing, mix together the vinegar and English mustard, add the oil, then the mint and peas. Toss dressing with the lettuce.
Serve four fingers per main course portion, stacking two one way and two on top, the other way. Serve immediately.