1. Put all the dressing ingredients in a jar and shake together.
2. Fry the garlic in the oil over a medium heat until golden and crispy. Remove from the oil with a slotted spoon and set aside.
3. In the same oil, stir-fry the prawns with the roasted cashew nuts for about 2-3 minutes until the prawns are just pink. Add to the garlic, spoon over 2 tablespoons of the dressing and set aside to cool.
4. When ready to serve, peel, stone, and dice the avocado, and toss together with the cabbage, mango, herbs, spring onions and prawn mixture. Serve immediately, handing round the remaining dressing in a separate bowl.