Preheat the oven to 190˚C.
Place the salmon in a roasting dish, cover with foil and place in the oven for 15 minutes to heat through.
Flake the salmon with a fork and place in a large bowl together with the mashed potatoes, butter, and mustard. Mix well.
Add the dill, parsley, chives, lemon juice and zest. Season well with salt and pepper and mix thoroughly.
Divide the mixture into 12 portions and form into balls. Flatten each ball to about 1cm thick.
Dip each fishcake in the seasoned flour, then the beaten egg and finally the breadcrumbs to coat each one.
Fry the fishcakes in 2 tablespoons oil over medium-high heat for 5 to 8 minutes on each side until golden brown and crispy.
Recipe courtesy of Le Creuset.