In a clean bowl, whip the egg white until it forms stiff peaks. Gently fold in the drained crab meat, canola oil, and seafood seasoning, if using. Be careful not to overmix to keep the lumps of crab intact.
Melt the butter in a nonstick skillet over medium heat.
Carefully spoon the mixture into the hot pan to form 3-4 small patties. Pan-sear for 2-3 minutes, until the edges are golden brown and crisp.
Flip the crab cakes carefully and cook the other side for another 2-3 minutes until cooked through and golden.
While the crab cakes cook, mix the mayonnaise and relish in a small bowl to create a quick tartar sauce.
Transfer the cooked crab cakes to a serving plate and drizzle any remaining flavorful butter from the pan over the top.
Serve immediately with the tartar sauce for dipping and fresh celery on the side.