Place the zucchini and capsicum into a large bowl. Sprinkle over salt and pour over 2 tablespoons of water. Mix well then leave to stand for 2 hours until softened. Drain well.
In a saucepan combine the KEEN’S Mustard Powder, sugar, bay leaf, vinegar, mustard seeds and McCormick Turmeric Ground. Bring to the boil and cook for 3 minutes. Remove from the heat and leave to cool.
Pour cooled liquid over the vegetables and spoon evenly between sterilised jars. Cover, refrigerate and leave for 2 days before using.