Cook the potato in a small saucepan of lightly salted boiling water for 6–7 minutes, or until tender. Drain well, transfer to a large bowl and mash with a potato masher. Set aside to cool to room temperature.
Meanwhile, to make the sauce, mix together the dill, vinegar, sugar, 1 tablespoon of the mustard and 1 1/2 tablespoons of water in a small bowl. Set aside.
Add the mayonnaise, lemon zest, lemon juice and the remaining mustard to the mashed potato. Add the salmon and mix together. Shape into four even-sized cakes.
Combine the breadcrumbs and parsley on a plate. Dredge the fishcakes in the crumb mixture, patting it on.
Heat the oil in a large non-stick frying pan over a moderate heat. Fry the salmon cakes for 4 minutes on each side, or until browned and cooked through. Serve the fishcakes with the sauce.
I left out the brown sugar, bread crumbs and parsley. I cooked the salmon patties on a sprayed pan, and served with the dill-mustard sauce. Other than an over whelming vinegar sensation, this tastes great and looks interesting! - 13 Apr 2010