Buffalo Chicken Macaroni and Cheese

Bring a large pot of water to a boil over high heat. Add the salt and the macaroni and cook for 7 minutes. Drain and set aside. 

In a large skillet over medium-heat, cook the bacon until crispy on both sides, about 4 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 bits (not too small but bite-sized). Set aside. 
In the meantime, in a large saucepan, melt the butter over medium-heat. Add in the onion and celery cook, stirring frequently, for 6 minutes, or until softened and nearly translucent.
Add in the garlic and cook for 1 more minute, or until fragrant.
Sprinkle in the flour, and whisking constantly, cook for 1 minute. Slowly pour in the buffalo sauce and milk, whisking constantly as you add. Cook over medium-high heat, whisking almost constantly, until the mixture bubbles up and thickens, about 5 to 6 minutes.
 Reduce the heat to low and slowly whisk in the heavy cream. Then stir in the cheddar cheese, pepper jack, cream cheese, and half of the blue cheese. 
Fold in the pasta and 2 cups of the shredded chicken and mix well. Cook for 2 more minutes, then remove from heat, top with remaining chicken, blue cheese, and bacon. Sprinkle with scallions and serve warm.