Get some good organic free range fellas. The yolks should be orange, not yellow. Make them in a Pyrex bowl over a pan of very very gently simmering water. Throw in the butter first and If the water goes too mental turn off the gas for a bit. It’ll take about ten minutes of constant stirring with a spatula, but it’s worth it. Season about halfway through and do not overcook them, so take the bowl off the pan just before they’re done and let the residual heat do the rest. They should have the pouring consistency of a risotto.
When made over very gentle heat like this the proteins in the egg give them a really nice texture and flavour. It’s the same reason Heston Blumanthingy cooks meat in a water bath and it works with eggs too. If you like your eggs well done then don’t bother.