Before starting the recipe; preheat your oven to 200°C / 392°F or gas mark 6.
Begin by carefully peeling the skin from the mushrooms.
Cut the stems from the mushrooms, set the stems aside for the filling; if you have small stems you’ll need 2 smaller mushrooms to make up the shortfall.
Place all of the other ingredients into a mini processor including the oil; pulse the machine until the ingredients are chopped small…..
If you don’t have a processor, use a knife to finely chop all of the dry ingredients and finally mix with the oil.
Place the 4 mushrooms on a baking tray and fill each one with the mixture. Don’t overfill as they will overflow in the oven.
Place the tray in the hot oven and set the timer for 12 minutes.
After the 12 minutes remove from the oven and serve.