Measure the ingredients while the chicken cooks. Set the heavy cream, milk, cheddar cheese, and cream cheese near the stove so they are not refrigerator-cold.
Submerge the chicken in a pot of water and gradually bring it to a gentle boil. Cook for 15 to 20 minutes, until chicken is cooked through.
Remove the chicken and use 2 forks to shred it. Toss with blue cheese dressing and set aside.
Begin boiling salted water in a large pot while you start the sauce. Once a boil is reached, add the pasta and cook until al dente according to package instructions. (Don’t overcook.) Drain and set aside.
Melt the butter in a pot over medium heat. Add the flour and stir continuously for 1 minute. Add the tomato paste and stir to incorporate, you’ll be left with a thick paste.
Add the heavy cream and milk in small splashes, stirring continuously. Doing this slowly ensures that the sauce stays thick.
Bring to a boil, then reduce heat to low.
Add the buffalo sauce, hot sauce, mustard powder, onion powder, and salt/pepper.
Gradually sprinkle in the cheddar cheese and cream cheese, stirring continuously.
Stir in the shredded chicken, then add the drained pasta. Use a silicone spatula to gently stir to combine. Serve!