I have tried this Jamie Oliver recipe twice and really like it as a casual canapé. The first time I followed the recipe but had to use fresh thyme instead of oregano as the supermarket in Sweden didn’t have any oregano. It was still delicious! Yesterday I used chilli flakes and dried oregano and that worked well too. Both times I have used chestnut mushrooms but they don’t taste much, so I think it would be even better with a more flavoursome mushroom.