Cook the spaghetti according to the instructions on the packet. Meanwhile, heat the olive oil in a large frying pan and fry the pancetta until crispy. Set aside to drain on kitchen paper.
Add the mushrooms and leeks and cook for 5-6 minutes, until they are soft. Return the pancetta to the pan. Add the light soft cheese with garlic and herbs and stir to combine.
Once the spaghetti is cooked, drain and return to the saucepan. Tip the sauce mixture into the pasta and toss to coat well.