Cut out 24 circles, from the rolled out sheet of pastry using a 5cm/2in pastry cutter.
Gently press the circles into the tartlet tins. Fork bottom of pastry. Cover with cling film and refrigerate.
Preheat oven to 200C/400F/Gas 6.
Heat the oil in a wide frying pan or wok.
Add the wild mushrooms and fry over a high heat. Season.
Add the soaked mushrooms. Fry for 1-2 minutes more, then remove from heat and transfer to a bowl to cool.
Finely chop the mushrooms or blend in a food processor until completely minced.
Transfer the chopped mushrooms to a large bowl, and add the remaining ingredients, ensuring that the mix is well seasoned.
Fill the puff pastry tartlets with one heaped teaspoon of mushroom mix per tartlet. You may need more or less depending on the size of the tartlet tins.
Bake for 10-12 minutes in the preheated oven, until pastry is golden and the mushroom mix has risen and expanded slightly.
When the tartlets have cooled slightly, drizzle with truffle oil and sprinkle with coarse sea salt.
Serve warm.
