Preheat the oven to 350 degrees F (gas mark 4 or 180 degrees C).
Heat the oil and fry the onion and garlic until soft. Grind the Delinut cashew nuts, then mix with the breadcrumbs. Mix in the mashed parsnips, rosemary, and thyme. Add the onion, being sure to scrape all the juices into the mixture.
Dissolve the yeast in the water and mix into the vegetable nut mixture. Season well.
Melt the butter in a skillet and saute the chopped mushrooms until soft. Grease a 2-pound loaf pan, then press in half the nut mixture. Cover with a layer of mushrooms and top with the rest of the nut mixture.
Press down well. Cover with foil and bake for 1 hour. When cooked, remove the pan and let stand for 10 minutes before turning onto a plate.
Serve hot or cold. Slice loaf to serve. Serve with vegetables or a crisp green salad.