
Dice the cabbage finely.

Dice the carrot and onions finely

Mix the diced vegetables, onion, mustard seeds (if using) and sugar evenly in a large mixing bowl. Add in the mayonnaise. Mix well until the consistency of the coleslaw is even.
Chill the coleslaw for at least an hour and serve chilled. Coleslaw can be kept in the fridge for up to 3 days.