Prepare the mushroom stock by breaking the dried porcini mushrooms into small pieces and soaking them in 200 ml of boiling water.
In a food processor, add the nuts and ground them by pulsing until they have the desired consistency and set aside. If you are making homemade bread crumbs, add the bread into the food processor and pulse until you have fine bread crumbs.
Preheat the oven to 200C/390F.
Heat some olive oil in a frying pan. Finely chop onion and garlic and add to the pan. Fry until translucent and add roughly chopped mushrooms and finely chopped rosemary. Sauté for a couple of minutes. Turn the heat off.
Add the grounded nuts and bread crumbs and mix together.
Pour the soy sauce, yeast extract and add the dried mushrooms stock, combine all the ingredients until a dough is formed and adjust with salt and pepper.
Spoon evenly onto parchment on a baking dish, drizzle olive oil and bake for about 40 minutes or until the top is browned.