Grease 3 litre shallow ovenproof dish. Heat oil in pan, add onion and garlic, stirring until onion is soft. Add spinach and herbs, cook, stirring until spinach is wilted and excess liquid evaporated. Stir in cheeses and nuts.
Spoon spinach mixture into piping bag without tube, pipe into cannelloni shells. Place shells in single layer in prepared dish, pour over tomato sauce. Bake, uncovered, in moderate oven for 30 minutes. Sprinkle with extra parmesan and bake further 10 minutes or until cheese is melted.
Tomato sauce: Heat oil in pan, add onion and garlic, cook, stirring, until onion is soft. Add undrained crushed tomatoes and sugar, simmer, uncovered for about 10 min or until thickened.