Heat the olive oil in a large frying pan.
Add the onion and cook over a medium heat for 10 minutes, stirring often, until soft.
Add the garlic and cook for a further minute.
Add the sliced courgettes and sauté for 10-15 minutes, stirring often, until brown on both sides.
Meanwhile, bring a large pan of water to the boil, adding salt if desired. Add the pasta and cook according to the packet instructions. Drain when cooked.
When the courgettes are cooked add the lemon zest and lovage, stir and warm through.
Lightly toast the sunflower seeds in a small frying pan. Mix the pasta with the courgette mixture and top with the sunflower seeds. Season with salt and pepper to taste.
Serve immediately with a salad.