Saute onion and garlic in the oil in a large non-stick frypan over medium-high heat. Cook for 5 minutes or until the onion is translucent.
At the same time, using hands or a cheese grater, crumble tempeh into small pieces.
Reduce heat to medium, add tempeh, celery, carrots and mushrooms and cook for 15 - 20 minutes.
Stir through tomatoes, basil, oregano and salt and pepper. Simmer for 10 minutes or until the liquid is slightly reduced. If the sauce becomes too thick, add a few tablespoons of water. Adjust seasoning.
Meanwhile, bring a large pot of salted water to the boil and cook pasta according to packet directions or until just tender. Drain and divide between serving plates.
Add sauce and top with cheese and basil leaves, if using to serve.
