Cook the penne pasta according to the package directions until al dente. Drain and set aside.
Meanwhile, in a separate large pot, melt the butter over medium heat. Once melted, add the flour to the butter and whisk to create a roux. Cook for a minute or two until the roux is golden and bubbling.
Slowly whisk the milk into the roux, ensuring there are no lumps. Add the hot sauce, garlic powder, salt, and black pepper to the milk mixture and stir to combine. Allow the mixture to come to a simmer, stirring frequently.
Once simmering, remove from the heat and add the cheddar cheese, stirring until it is melted and the sauce is smooth.
Stir in the ranch dressing and crumbled blue cheese and mix well.
Add the cooked chicken to the sauce and stir to coat evenly.
Add the cooked penne to the saucepan and stir to evenly coat the pasta with the sauce. If desired, garnish with green onions and additional blue cheese (optional) and serve warm.
Notes
Hot sauce: Frank's RedHot Original and Louisiana Hot Sauce have the same Scoville rating and are considered to be mild sauces. For a more mild cheese sauce, start with half of the hot sauce and add from there. To increase the spiciness, add more sauce or try Texas Pete's Original Hot Sauce.Storage: Allow the pasta to cool down to room temperature before storing. Transfer the leftovers into an airtight container or resealable plastic bag. Store the leftovers in the refrigerator within 2 hours of cooking. Enjoy the leftovers within 3-4 days.Freezer: Freeze the sauce separately and then make fresh pasta when you're ready to eat it. Let the sauce cool completely. Transfer the sauce to freezer-safe containers or heavy-duty freezer bags. Thaw it overnight in the refrigerator. Reheat it in a saucepan over medium heat, stirring occasionally. While the sauce is reheating, cook the pasta according to the package instructions.