butter a 9x12" pan (a disposable foil one is fine) Bake the bacon on a shallow pan in the oven @ 400 degrees for 20 mins, flip, and bake for 5 mins more. Remove the bacon to paper towels to drain while prepping the rest of this dish. Turn the oven down to 350 degrees. (Hint: I lightly coat the bacon with Wondra flour before baking it. This cuts down on the splattering in the oven and makes the bacon nice and crispy.)
Shred your cheeses together in a bowl. Boil water and cook elbow macaroni, stirring constantly, for 7 minutes. Drain pasta and place in buttered baking dish.
In medium sauce pan, pour in quart of heavy cream, add the Dijon mustard, salt and cayenne pepper. Bring to boil, reduce temp and begin stirring the shredded cheeses, adding a handful and stirring in completely before adding the next handful.
Pour cheese sauce over macaroni in pan and mix well. Add in the scallions and crumble in the bacon. Mix well to evenly distribute the scallions and bacon.
In a small bowl combine bread crumbs, parmesan cheese and Extra Virgin Olive oil to create a crumbly topping. Sprinkle this topping all over the top of the macaroni in the pan.
Bake for 30 minutes in 350 degree oven. Dish is done when the topping is golden brown and some cheese is bubbling through the topping. Remove from oven and let set for 5 minutes and serve.