Elevated Macaroni and Cheese with Bacon and Gruyère

Preheat the oven to 375 degrees (F). Lightly grease a 3-quart baking dish and set side until needed. 
Bring a large pot of water to a boil over high heat. Add the salt and shellbows and cook for 6 minutes. The pasta will be very al dente. Pour pasta into prepared baking dish and set aside until needed.
In a large skillet over medium-heat, cook the bacon until crispy on both sides, about 4 to 5 minutes per side. Remove from heat and place on a paper towel lined plate. Blot any excess oil with a paper towel, then chop into small bits. Set aside. 
In a large pan, melt the butter over medium-heat. Add in the chopped shallots and thyme and cook, stirring frequently, for 5 to 6 minutes, or until softened and nearly translucent. 
Sprinkle in the flour, and stirring constantly, cook for 1 minute. Slowly pour in the milk, whisking constantly as you add. 
Cook, whisking constantly, until the mixture begins to thicken, about 5 minutes. Whisk in the brown sugar, salt, pepper, cayenne pepper, and nutmeg.  
Remove the pan from heat. Immediately stir in the heavy cream, then add the extra sharp white cheddar, gruyère, sharp cheddar. Fold in half of the chopped bacon.
Pour sauce over cooked pasta and stir gently to combine. 
In a small bowl combine the bread crumbs and olive oil, mixing well until the bread crumbs are evenly coated in the oil. Sprinkle on top of the macaroni and cheese. 
Place the baking dish in the preheated oven and bake for 20 minutes. Sprinkle the top with remaining bacon and bake for an additional 5 minutes. Serve warm!