Preheat your oven to 350 degrees Fahrenheit and grease a 9×13 inch baking dish with butter. Fill a large pot with water and a generous pinch of salt, then bring it to a rolling boil. Add the elbow pasta and cook it 3 minutes shy of al dente, as it will continue cooking in the oven and absorb the sauce. This al dente stage ensures the noodles swell perfectly without becoming mushy during baking. Drain the pasta well but do not rinse it, preserving the starch that helps the sauce cling to the noodles.​​

In a large pot over medium heat, melt the 1/3 cup of unsalted butter completely. Once melted and bubbling gently, whisk in the 1/3 cup of flour. Stir constantly for a full minute until the mixture becomes foamy and blonde in color, cooking out the raw flour taste to avoid graininess. This roux is key to a smooth, thick sauce that coats every piece of pasta evenly, creating that signature creamy emulsion.​​

Slowly pour in the 2 cups of milk and 2 cups of heavy cream while whisking vigorously to prevent lumps. Use whole milk for richness, as lower-fat options thin the sauce. Cook on medium-low heat, stirring often, until the mixture thickens enough to coat the back of a spoon, about 5 to 7 minutes. Add pinches of paprika, granulated garlic, nutmeg, salt, and pepper. The nutmeg enhances the cheeses’ flavors subtly without overpowering, while paprika adds a hint of warmth.​​

Remove the pot from heat. Stir in the 4oz of softened cream cheese until fully melted and smooth, boosting creaminess. Gradually whisk in about two-thirds of the cheeses: 2 cups white sharp cheddar, 2 cups yellow sharp cheddar, 1 cup Gruyere or Swiss, and 1/2 cup Parmigiano. Add them in small batches off the heat to melt evenly into a luscious sauce. Freshly grate all cheeses yourself; pre-shredded versions contain anti-caking agents that prevent smooth melting and result in graininess.​​

Add the drained al dente pasta directly to the cheese sauce. Toss thoroughly to coat every noodle generously; the mixture will look soupy, but the pasta absorbs excess liquid during baking for ideal consistency. Taste and adjust seasoning if needed. Pour into the greased baking dish, spreading evenly.​

Sprinkle the remaining one-third of the grated cheeses evenly over the top for a golden, bubbly crust. Cover the dish with foil and bake for 15 to 20 minutes to set the center without drying out.

Uncover and bake another 20 to 25 minutes until the top is deeply browned and the edges bubble. Let rest 10 minutes post-bake; this allows the sauce to thicken further into perfection.​