To make the broth, mix together the stock, palm sugar and fish sauce in a pot and bring to the boil. Remove the broth from the heat, add the sesame oil and keep warm.
Dissolve the palm sugar in the fish sauce, then whisk in the eggs. Gently mix together the bean sprouts, snow pea sprouts, chives and crabmeat in a separate bowl.
Heat a wok until just smoking. Add