1/ Make the poaching liquid. Put the stock in a saucepan over a medium heat. Roughly chop the ginger, peel the garlic and crush with a knife and add both to the stock along with the Sichuan peppercorns. Cut the chicken thighs into thirds and add that and the broccoli florets to the stock. Bring to a simmer and then turn down the heat and cook slowly for about half an hour.
2/ For the sticky sauce. Grate the garlic, and ginger and add into a large non-stick pan with the rest of the sauce ingredients. Put the pan on a medium heat, add the chicken, broccoli and cashews. Give it all a good mix and cook for about 15 mins, stirring regularly, until the sauce reduces and becomes sticky.
3/ Slice the spring onion and scatter that over to serve.
