Get a pot of water going for your noodles. You can start your noodles while making this sauce, because this is a very quick recipe.
First you need to make a rue. You do this by melting the butter in a large saucepan, then adding the flour. With a rubber spatula, mix the butter and flour together until it gets creamy. Then add your milk. You'll have to stir fairly often - milk will burn if you leave it unattended. The sauce should start thickening and bubbling after a few minutes. Add in your crushed garlic then.Then add your chicken and salt and pepper.
You can also add in your cajun spice now. Kevin and I like more heat than our children do, so we lessen the heat for them, and then crank it up after we serve their plates. It just depends on how spicy you like things. Three teaspoons is average on the spice scale. Adjust to your preference.
I have added all kinds of veggies to this pasta too - usually whatever I have in the fridge/freezer. Broccoli, asparagus, onions, peppers - whatever veggies you like. If you want veggies, saute those before making your rue. Then using the same pan as you did for your veggies, take them out and add them back in when you add in your chicken. Or, for an extra yumminess, use leftover grilled veggies! THAT would be ideal.
If you want to REALLY show off, add some cheesy garlic bread(a.k.a. Patti Bread) to serve with the pasta. Everyone will LOVE you!