Put a pan of salted water on to boil; add the tagliatelle according to the packet’s instructions. Drain, reserving a small ladle full of cooking water, and set aside
Heat a little oil in a pan and fry the peppers until softened (about 10 minutes) – the longer and slower they cook, the sweeter they are
Add the pesto, spinach and cooked prawns to the pan – gently heat through