To crack a soft-cooked egg, tap around the top third of the shell with a butter knife, and gently pull it off. If you'd like, you can substitute toasted fennel seeds or celery seeds for the coriander.
Toast coriander seeds in a small dry skillet over medium heat until fragrant, about 3 minutes. Transfer to a spice grinder or a mortar and pestle. Add salt and pepper, and finely grind together.
Bring a medium pot of water to a boil. Gently place eggs in water, and simmer 4 minutes. Remove from water, and place, wide side down, in 6 egg cups or ramekins. Serve with coriander salt.