Whisk together eggs, mustard, pepper and Cajun seasoning.
Add chopped cod, onion and relish, mix well and add breadcrumbs.
Spray non stick frypan well with veggie spray, heat to a sizzle. Divide cod mixture into 4 patties, brown well , approximately 5 minutes; turn and brown other side for another 5 minutes. turn onto a hot platter and garnish with ketchup or chili sauce.