8 large chestnut mushrooms
1 lime, juice and zest
2 sprigs rosemary, leaves finely chopped
1 heaped tbsp dark brown sugar
½–1 tsp cayenne pepper (or less if you prefer a milder dish)
2 tbsp olive oil
1 tsp sea salt flakes, plus extra to serve
225g/8oz paneer, cut into 2cm/¾in cubes