In a medium skillet, cook bacon until crisp. Remove and keep warm. Pour off all but 1 TBP of drippings. Add leeks and cook, covered over medium-low heat, stirring occasionally until tender - about 6 minutes.
In a large bowl, whick together remaining 4 TBSP oil, vinedar, mustard and remaining 1/4 tsp salt and pepper. Add lettuce and toss until well coated.
Arrange lettuce on 6 serving plates. Top with mango, bacon, leeks, cheese and raspberries.
Emmental or Comté may be used instead of Fol Epi.