To poach the salmon:
Place all the ingredients, except the salmon, into a shallow sauté pan or wide saucepan deep enough to take the piece of fish. Lay the salmon in the poaching liquid, which should reach about halfway up the pan, almost covering the fish. Place on a low heat and allow the liquid to come to simmering point. Cover with a lid, or a piece of close-fitting foil, and cook gently over a low heat for three minutes, turn off the heat and leave to cool with the lid or foil in place.
When cool, remove the fish and strain the cooking liquor through a sieve, into a bowl. Discard the ingredients in the sieve. Before pouring the poaching liquor into a measuring jug, first measure Basmati rice in the jug, up to the level of 10fl oz. Pour the rice into a sieve and rinse it under cold running water until the water runs clear and set aside to drain. After measuring the rice, pour the poaching liquor into the jug. You will need 20fl oz. of liquid to cook the rice. If short on quantity, make it up to the correct amount with some cold water.
To cook the rice and complete the dish:
Melt the butter in a medium-size, thick-bottomed saucepan, which has a close-fitting lid. Soften the chopped onion in the butter and allow to cook for a few minutes. Add the washed rice, crushed cardamoms, lemon zest and a good pinch of sea salt. Stir well and pour in the poaching liquor. Bring to the boil and immediately cover with the close-fitting lid, or a layer of foil plus the lid. Turn the heat down very low for exactly 15 minutes and then turn the heat off, but do not remove the lid from the rice for at least a further 10 minutes. Don't cheat and be tempted to look before 10 minutes is up!
While the rice is cooking, discard any skin and flake the poached salmon into a large mixing bowl. Add the finely chopped hard-boiled eggs, spring onions, flaked hot-smoked salmon and peat-smoked salmon cut into small pieces.
Once the rice is cooked, remove the cardamoms and add it to the salmon mixture. Fold ingredients together well with a large metal spoon. Just before serving, stir in the fresh herbs and check seasoning. The whole dish can be cooled completely and stored in an airtight container in the refrigerator at this stage. Individual portions can be reheated, but never reheat rice more than once.
To serve, add a small knob of butter and a tablespoonful of cream per person and reheat slowly and thoroughly over a low heat. Alternatively, this dish reheats per portion in a microwave very successfully. Serve piping hot with wedge of lemon and additional hard-boiled eggs quartered as a garnish if liked.