Heat the oven to 200ºC (180º fan), gas 6.
Heat the oil in a wide pan and gently cook the onion for 3 minutes until soft but not brown.
Add the bacon and chilli, cook for 5 minutes then stir in the sweet corn, bread crumbs, lime juice and zest and the parsley then season the mixture with salt and pepper.
Remove the stalks from the mushrooms and discard.
Place the mushrooms in an ovenproof dish and spoon the stuffing into the middle of each.
Bake in the oven for 20 - 25 minutes and serve immediately.