Pre-heat oven to 400 °F and coat a 9 x 13" baking dish (or two if you are making a double batch) with cooking spray.
Cook pasta according to box directions. Add 1-2 tablespoon of salt to the water before mixing in the pasta. After draining the pasta pour it directly into the baking dish(es).
Meanwhile, start the roux. Melt butter in a medium saucepan over medium-low. Whisk flour into the butter and continue to whisk frequently for about 1 minute.
While whisking, carefully pour in the beer and allow to heat for about 2 minutes. If the beer starts to foam too much, turn down heat and lightly mix. Then, mix in milk and buffalo sauce.
Bring mixture to a simmer. Keep an eye on the sauce at this point because the beer may foam up. Mix gently to reduce any excess foam.
Turn the heat down to medium-low again. Wait until the mixture stops simmering; you want the milk to cool slightly before the cheese is added. While mixing add in cheese 1 cup at a time. Allow the cheese to melt into the milk mixture before adding more.
Season the cheese sauce with garlic powder, salt, and pepper. Taste cheese sauce and adjust to taste. The cheese sauce should be a little salty because it will taste less salty after baking.
Combine the pasta and sauce. Pour a little less than half of the cheese sauce over the pasta in the baking dish(es). Use a spatula to fold the sauce into the pasta. Add more sauce as desired. The pasta should be coated with a little excess sauce because it will bake down.
Sprinkle the bread crumb mixture evenly over the top of the pasta. If you prefer a slightly moister bread crumb, you can add thin pats of butter over the top of the bread crumbs before baking or melt 1 tablespoon of butter and mix it in with the crumb before sprinkling.
Bake for 25-30 minutes, until the top of pasta is lightly browned.
If you made a single batch, freeze the extra sauce in a medium freezer-safe container. When you are ready to use the sauce, heat it slowly in the microwave, adding 1-2 tablespoon of milk as needed to thin it to the proper viscosity.