Put the rice in a bowl and pour over cold water. Swirl the rice around with your fingertips; the water will become cloudy from the dust and flour on the grains. Pour off the cloudy water and repeat the washing until the water runs clear.This will require 4 or 5 rinses. Cover the rice with fresh water and add the 2 tablespoons of salt. Stir well. Leave to soak for at least 30 minutes, preferably an hour.
Bring a pan of water to the boil, add the eggs and reduce the heat to a simmer. Cook for 15 minutes. Pour off the water and add cold water to cool the eggs.
Melt the butter in a pan and add the onions. Toss in the butter and sprinkle over the remaining salt and pepper. Fry gendy over a medium heat until the onions are golden and crisp at the edges. Set aside.
Drain the rice and rinse under running water to wash away the salt. Bring at least 2 litres of water to the boil, tip in the rice and cook for 3 minutes.Tip in the rinsed lentils and cook for a further minute. Taste and check for done-ness. Turn off the heat and drain the rice and lentils through a sieve. Put the sieve back over the pan and cover with the lid. Leave to steam dry for 10 minutes.
Fluff the rice and lentils with a fork and add to the pan with the onions. Toss gently to mix.
Remove the shells from the eggs and cut into quarters. Transfer the rice mixture to a warmed serving plate and tuck the egg quarters around the dish. Garnish with a little chopped parsley and serve.