Grind all the relevant ingredients into a fine paste, adding a little water if you need it.
Rinse & dry the salmon and cut about 4-5 slashes on both sides, depending on the size of the fish.
Oil the roasting dish and arrange the potatoes around the base of the dish, single layer or overlapping, it doesn't matter.
Scatter the leeks on the potatoes and sprinkle some salt all over, followed by half the lime slices.
Rub the marinade all over the salmon, making sure to get in the slits well and coat the cavity thoroughly.
Place the salmon diagonally on the potatoes, don't worry about overhang of head and tail.
Stuff the cavity with the lime leaves and the rest of the coriander leaves and lime slices.
Roast on 220˚C for 20 minutes, then lower the heat to 180˚C and cook for another 45 minutes or so, depending on the size of the fish.
To taste for doneness, slide a butter knife into the thickest part of the fish, take it out and place the knife on your hand, between your thumb and forefinger. If the knife feels hot, the fish is done. Seriously.
Take it to the table and let everyone help themselves. Scatter with some fresh coriander & a squeeze or two of lime juice will go perfectly.