Cook pasta according to package directions. Salt the water so you don't have bland pasta. I add about 1 teaspoon salt into the boiling water with the pasta.
In a sauce pan, over medium heat, melt the butter. Add the garlic and cook and stir for 30 seconds. Add the flour and stir with a whisk for 30 seconds. It will be a thick paste. That's ok.
While whisking, slowly add in the chicken broth, milk, salt, and pepper. Stir and cook for several minutes until mixture has thickened. Careful not to let this boil and burn. Lower the heat if needed. You don't have to stir constantly, but you should stir very often.
Once sauce is thickened, take off the heat and add in the dried parsley and shredded parmesan cheese. Let melt and then stir together to combine.
Drain the pasta but DO NOT rinse it. Add the creamy sauce to the cooked pasta and stir together. Serve!
** It helps a lot to have everything ready to go before you start making the sauce. It does go pretty quickly. Measure out the flour, spices, and combine the liquid together into a 2 cup glass measuring cup, and have the parmesan cheese already shredded. That way everything is ready to go. **
I don't really ever measure the parmesan cheese. I buy the 5 oz wedge and it's a little more then 1 cup shredded. I just add it all in.
Any milk will work. The higher fat percentage the faster the sauce will thicken. I have used skim milk with great results too.