
Heat a small pan to medium heat. Add the mustard seeds, black peppercorns, coriander seeds, allspice berries, cardamom seeds, celery seeds, and whole cloves. Lightly toast them in the dry pan for 1 minute, shaking/stirring a bit, to let the spices bloom.
Transfer to a food processor/spice grinder along with the red pepper flakes, ground ginger and bay leaves.
Process to a coarse blend, or to your preferred consistency. Use as desired.