Cook the tagliatelle in a large pan of
boiling, salted water according to pack
instructions. Four mins before the end of
the cooking time, add the runner beans.
Meanwhile, cut each slice of prosciutto
into 5-6 pieces. Heat the oil in a frying pan,
add the ham, then fry quickly until crisp.
Drain the pasta and return to the pan with
the crème fraîche, prosciutto, pan juices and
plenty of black pepper, tossing everything
together until the pasta is well coated.