Fry mushrooms and garlic in oil and butter for two minutes then drain thoroughly.
Fry the trimmed leeks in the same manner and drain well until solid.
Mix ricotta and cream cheese with seasoning in a bowl until smooth.
Fold mushrooms, leeks, and tomatoes into the cheese mixture and chill for 2 hours.
Preheat the oven to 200°C.
Layer three sheets of pastry per strudel, brushing each with melted butter.
Place a portion of filling at the bottom edge of each pastry stack.
Fold and roll the pastry into a tight parcel and brush with butter.
Bake the strudels on a tray for 25 minutes.
Sauté onion, sauce mushrooms, and garlic in oil until soft.
Add vegetable stock and boil until almost evaporated.
Pour in wine and port then reduce the liquid by half.
Whisk cold butter cubes into the sauce until glossy.
Serve the strudels on a pool of the prepared sauce.