Cook the pasta in a large saucepan of salted boiling water according to the packet instructions until al dente. Drain.
Meanwhile, heat the oil in a large frying pan over a high heat until the surface of the oil seems to shimmer slightly. Add the prawns, garlic, lemon rind and chilli, season with salt and cook, stirring, for 2 minutes until the prawns turn pink. Add the courgettes and butter, season with a little more salt and stir well. Cook, stirring, for 30 seconds.
Toss in the pasta and stir until the butter has melted and all the ingredients are well combined. Serve immediately.