Step 1

Preheat your oven to 375 degress F.

Step 2

Boil the cavatappi pasta according to the directions but take it out and drain 1 - 2 minutes early. The pasta will further cook when it's baking in the oven so we do this to avoid overcooking the pasta.

Step 3

Make the roux: Melt the butter in a pot over medium heat. Once it's melted, add in the flour and stir quickly using a flat spatula. Make sure to scrape the bottom and sides and continue stirring for 3 minutes. Make sure the roux doesn't get dark and stays a pale yellow color.

Step 4

Make the bechamel sauce: Slowly drizzle in the warm milk into the pot while stirring vigorously with a whisk. Add in the diced onions at this time. Stir continuously for about 5 - 7 minutes until the roux and milk have combined and the sauce has thickened. Make sure to scrape the bottom and sides. The bechamel should be thick enough to coat the back of a spoon.

Step 5

Add the cheese: Turn off the heat and add ¾ of the gruyere and cheddar cheese to the pot. The rest will be used on top of the mac and cheese. Stir the sauce and cheese together until the cheese has fully melted. At this time, you can taste for salt and pepper. You may not need any depending on the saltiness of your cheese. Add in cayenne powder if you prefer a little spice.

Step 6

Add your cooked pasta to a baking dish and pour the sauce over the pasta. Mix it well until the pasta is completely covered. Top with the remaining ¼ shredded cheese.

Step 7

Melt the butter in a pan and then add the breadcrumbs and toss together until the breadcrumbs are evenly coated. Add in the optional truffle oil at this time.

Step 8

Spread the breadcrumbs evenly on top of the shredded cheese.

Step 9

Bake the mac and cheese on the center rack in the oven for 30 - 35 minutes. If the breadcrumbs start to get too dark, cover the mac and cheese with foil and turn down the heat to 350.