For the Mornay: Render bacon in a skillet and reserve the fat, drain bacon on a paper towel and then chop fine. In a separate saucepot, pour in the bacon fat, add butter, place over medium heat and then whisk in flour. Stir over low heat for 3-4 minutes. Add milk and cream and stir until smooth. Increase heat to medium high and stir to thicken, then reduce heat, add cheeses and continue stirring to make sauce velvety smooth.
For assembling: Add cooked pasta, chopped bacon, scallions, herbs and seasonings and serve.