I couldn’t get hold of the black bean paste, but used 4tbsp of Laoganma instead (when serving 4). Doing this is easier if you’ve not got immediate access to a Chinese supermarket (most major supermarkets in London stock it in the world food section). Laoganma is preserved black beans in chilli oil, so I didn't bother including the fresh chillies!
Serve with some jasmine rice and you’re all good to go. It only took about 10 minutes to prep, and 15 minutes to cook with minimal effort so it’s definitely one to try!