The simplest method would be to simply have a soft start which ramps the PWM duty cycle slowly in order to limit the RMS current through the FET until the element starts to heat. That should work, assuming the FET can withstand narrow pulses of high current. Using a NTC ICL is also an option, though it will waste some power. A series inductor probably isn't feasible, since the thermal time constant of your element is probably very long (seconds), it would take a huge inductance to match that.