Cook and shred or chop your chicken if you have not already.
Fill a medium-large pot with water and bring to a boil over high heat. Add your pasta and cook according to the instructions on the box. Reserve about 1 cup of pasta water, then drain and set aside.
Meanwhile, in a separate medium-large pot over medium-low heat, add the butter, red pepper flakes, and black pepper. Once the butter has melted, let the spices sizzle in it for about 30 seconds. Stir in the tomato paste and cook for 1 minute or until it darkens in color, stirring often.
Whisk in the soy sauce, vinegar, and garlic powder until combined. Turn off the heat.
In a small bowl, whisk together cheese, yogurt, egg, and salt. Slowly whisk in about ⅓ cup hot pasta water (or use hot water).
Turn the heat back onto medium-low (you want the tomato mixture to be warm when you pour the cheese in). Stir in the cheese mixture until combined and the cheese starts to melt a little, about 30-60 seconds.
Immediately add the pasta and chicken and stir vigorously for about a minute or until the sauce is thickened and coating the pasta (it will be saucy!).
Serve topped with blue cheese and black pepper.