Place porcini, port and 1 cup water in saucepan. Bring to boil, then simmer for 5 minutes.
Remove mushrooms and set them aside. Bring liquid to the boil again and boil again for a further five minutes or until reduced to 2/3 cup of liquid.
Meanwhile finely chop the porcini mushrooms.
Heat oil and butter in large fry pan. Add onion and fry over med heat 2-3 mintues. Add the garlic, reserved porcini and mixed mushrooms and thyme and cook for 2-3 minutes. Add ½ cup of the port liquid and the lemon juice and season well. Continue cooking until all the liquid has been absorbed, then set aside to cool. Once cool process til almost smooth. Place in serving dish and refrigerate for ½ hour.
Once the pate has chilled, place the gelatine in small bowl of cold water to soften. Heat the reserved port liquid until warm. Squeeze excess water out of gelatine and add to the port. Stir over low heat until the gelatine is completely dissolved.
Allow to cool before carefully pouring the port jelly over the pate.