If there is one universal comfort food, we’d argue that it’s mac and cheese (and we dare you to prove us wrong). And of all mac and cheeses, chef Alex Guarnaschelli’s three cheese delight is up there on our list of favorites. 'Nuff said.
Preheat the oven to 350 degrees.
In a large pot, bring the water to a rolling boil. Add the salt and bring the water back to a boil. Taste the water. It should be salty like sea water. If it's a little faint in salt taste, add additional salt. Add the macaroni and stir, with a wooden spoon or large slotted spoon, to ensure the macaroni does not stick to the bottom of the pot as it cooks. Cook until the macaroni is still quite firm, 8-10 minutes.
Pour the macaroni and water into a strainer placed over the sink. Allow the water to drain out, reserving approximately 1 cup of the liquid.
In the same pot, bring the cream and the reserved cooking liquid to a simmer. Add the Dijon mustard and ¾ cups of the Gruyère. Season with salt and pepper to taste. Simmer gently; stirring constantly, until the cheese is melted and has integrated with the cream. Add the Parmesan and Cheddar. Stir with a wooden spoon and simmer again until smooth. Add a splash of Worcestershire and a splash of Tabasco. Stir to blend. Taste for seasoning.
Add the macaroni to the cream and stir gently to blend. Allow the macaroni to “rest” on the stove, 5-10 minutes, so the pasta absorbs the flavors. If needed, add the remaining Gruyère. Transfer the macaroni to an ovenproof baking dish (about 9 by 13 inches) and top with the breadcrumbs. Bake in the oven for 15 minutes before removing and serving a plate.