Heat a large saucepan, then fry the leeks
and bacon over a medium heat for 5 mins,
until the bacon is crisp and the leeks have
started to soften. Pour in the stock and stir in
the rosemary with some seasoning. Bring to
the boil, then simmer for 5 mins.
Tip in the pasta of your choice and continue
to cook for about 10 mins until the pasta is
'al dente'. Serve with warm, toasted ciabatta.