Wash the quinoa in cold water until it starts to run clear. Put in a saucepan, cover with cold water and add a pinch of salt. Bring to the boil and simmer for 15–20 mins until the quinoa is well cooked and the grain has started to unfurl. Drain, cool and set aside until needed.
To make the sauce, put the physalis and sugar in a saucepan and add enough water to half-cover the contents. Cook slowly over a low heat for 10-15 mins until the water has reduced by two-thirds and the physalis are soft. Remove from the heat and leave to cool. Transfer to a small food processor or blender and blitz until smooth.
Next, make the dressing. Put all the ingredients in a bowl and mix together well. Add the broad beans, coriander and chilli to the quinoa and mix well. Add 1 1/2 tbsp of the dressing, making sure you don’t soak the quinoa mixture too much.
To assemble the salad, put a deep 12-15cm ring mould on a plate (or use a large cookie cutter). Arrange the avocado in the bottom of the mould and, using the back of a spoon, press down firmly. Fill the rest of the mould with the quinoa and broad bean mix, and press down well again. Drizzle 1 tbsp of the physalis sauce around the edge, then remove the mould. Finally, mix together the onion and tomato and put 1 tbsp of this on top of the quinoa. Alternatively, simply tumble the salad onto a plate. Add more dressing if you feel it’s needed.