Slice the bottom off each mushroom, then place the tops on the griddle, flat side down.
Wrap some string around the thyme to make a brush.
Put the brush end with a large pinch of salt in the mortar and then bash, adding about 5 teaspoons of extra virgin olive oil and the white wine vinegar.
Add a bit more salt and pepper.
Using the thyme bundle as a brush turn the mushrooms over and brush with the thyme oil- keep dabbing them while they are cooking.
When the mushrooms are cooked, place them on a serving plate and sprinkle them with the parsley, chilli and lemon zest. Squeeze over the lemon juice and drizzle with extra virgin olive oil. Add a little balsamic vinegar if you like.