Step 1In a dry frying pan, toast together the sesame, coriander, cumin and nigella seeds over medium heat until fragrant, stirring or shaking the pan often, 3 to 4 minutes. Remove from heat.
Step 2Grind the seeds with a mortar and pestle or briefly in a coffee grinder, so that the sesame seeds do not release too much oil.
Step 3Oil your hands to prevent the cheese from sticking. Roll the cheese into 1-inch balls and chill uncovered on a greased baking sheet.
Step 4In a small bowl, mix the sesame seasoning with the salt and the chopped pistachio nuts. Roll the cheese balls in the mixture until well covered. Serve immediately, or cover and chill on a wax-paper-lined baking sheet until serving time.