Preheat oven to 350°F. Spray a 15x10 inch (or bigger) casserole dish with nonstick spray. Bring a large pot of salted water to a boil.
Cook noodles according to package directions, drain, blanche with warm water, and toss into the greased casserole dish. Set aside.
Meanwhile, in a large pot, melt butter over medium high heat. Add onion and garlic and sauté until softened, about 5-6 minutes.
Add flour and seasonings coating well to form a roux until all butter is absorbed. Allow the roux to brown a bit, stirring frequently for 3-4 minutes.
Add milk to the roux 1 cup at a time whisking constantly until smooth and the sauce thickens. Repeat until all milk is added and sauce has thickened.
Once all milk is added and sauce is thickened, reduce heat to low and add half of the gouda, half of the Italian blend cheese, and all of the brie. (If you were unable to find garlic herb brie and are using plain brie or camembert, add 1 tbsp garlic powder as well as a couple pinches of fresh chopped parsley and fresh chopped chives at this time as well.) Whisk constantly until all cheese is melted and creamy. It may take some time for the brie to break down and melt. This is normal.
Pour all sauce over the noodles in the prepared casserole dish. Mix well to fully coat all noodles. Top with remaining gouda and Italian blend cheeses. Bake for 30 minutes.
(Optional) If using topping, melt butter and stir into the breadcrumbs 3-5 minutes before the mac and cheese finishes baking. After the mac and cheese is done baking, change the oven to the broil setting and spoon the buttered breadcrumbs evenly over top of the mac and cheese. Broil for 1-2 minutes or until the breadcrumbs have toasted and are a nice, crispy golden brown.
Let cool for 5 minutes, then serve and enjoy!