1.Cook pasta in medium saucepan of boiling water, uncovered, until tender.
2.Meanwhile, cook pancetta in heated oiled medium frying pan until crisp; chop coarsely.
3.Melt butter in same frying pan; cook leek, stirring, until soft. Add cream; bring to a boil. Reduce heat; simmer, uncovered, 2 minutes.
4.Add leek mixture to drained pasta with half the pancetta and remaining ingredients; toss gently then sprinkle with remaining pancetta.