1.In a large saucepan of boiling salted water, cook spaghetti following packet instructions. Drain, reserving ¼ cup cooking liquid. Set aside.
2.In a large, deep frying pan, heat 2 tablespoons of the oil on medium. Fry half the zest and 1 crushed garlic clove for 1 minute. Add breadcrumbs and cook, stirring, for 4-5 minutes until crisp and golden. Transfer to a bowl.
3.In same frying pan heat remaining oil on medium. Saute remaining zest, garlic and chilli for 2-3 minutes, until softened.
4.Add pasta, reserved cooking liquid, lemon juice, parmesan and parsley, stirring to coat. Serve sprinkled with feta and crumbs.