In a large skillet over medium heat, add bacon, leeks, mushrooms and salt and pepper to taste. Cook for 10 minutes, until bacon is very brown and crispy.
Transfer bacon mixture to a paper towel lined plate.
Remove all but 1 tablespoon of the bacon fat from the skillet. To the skillet, add the endive. Cook for 5 minutes, until slightly tender.
In a large bowl, toss the remaining 4 ingredients (vinegar through honey), and add the bacon mixture and the endive. Serve warm.