Step 1: Cook the Chicken
Preheat your oven to 400°F (200°C). Pat the chicken breasts or thighs dry with paper towels. Place them on a baking sheet, drizzle with olive oil, and season generously on both sides with garlic powder, onion powder, salt, and pepper. Roast for 20-25 minutes (for breasts) or 25-30 minutes (for thighs), or until the internal temperature reaches 165°F (74°C). Remove, let rest for 5-10 minutes, then use two forks to shred the chicken into bite-sized pieces. Set aside. (Pro-Tip: This can be done ahead, or use a rotisserie chicken for ultimate speed.)

Step 2: Cook the Pasta
While the chicken roasts, bring a large pot of heavily salted water to a rolling boil. Add the penne and cook according to package directions until al dente (typically 10-12 minutes). Reserve 1 cup of the starchy pasta water before draining. Drain the pasta but do not rinse it; the starch on the surface helps the sauce adhere.

Step 3: Build the Roux (The Sauce Foundation)
In a large, deep skillet or Dutch oven (big enough to hold all the pasta later), melt the butter over medium heat. Once foaming, whisk in the flour to form a paste (the roux). Cook, whisking constantly, for 1-2 minutes until it turns a light golden color and smells nutty. This cooks out the raw flour taste.

Step 4: Create the Creamy Base
Slowly, in a thin stream while whisking vigorously, pour in the warmed milk and chicken broth. Ensure each addition is fully incorporated before adding more to prevent lumps. Continue whisking until the mixture is smooth and begins to thicken, about 5-7 minutes. It should coat the back of a spoon.

Step 5: Infuse the Buffalo Ranch Flavor
Whisk in the entire packet of ranch seasoning (or homemade blend), the minced garlic, and the Frank’s RedHot sauce. Let the sauce simmer gently for 3-4 minutes, stirring frequently, to allow the flavors to meld and the sauce to thicken to a creamy, gravy-like consistency.

Step 6: Finish the Sauce with Creamy Richness
Remove the skillet from the heat. This is crucial to prevent curdling. Whisk in the room-temperature sour cream until completely smooth and integrated. Taste the sauce now—this is your chance to adjust. Add more hot sauce for heat, salt/pepper, or a pinch of cayenne.

Step 7: The Grand Assembly
Add the drained, hot penne pasta and all of the shredded chicken to the sauce in the skillet. Using a large spoon or tongs, toss everything together with great enthusiasm until every piece is gloriously coated. If the sauce seems too thick, add the reserved pasta water a few tablespoons at a time until it reaches your desired creaminess. Finally, sprinkle in most of the shredded Monterey Jack (and blue cheese, if using), reserving a little for topping, and toss once more until the cheese just starts to melt into the sauce.