Start by bringing a large pot of salted water to a boil. Add your pasta and cook according to the package directions until al dente. Reserve about 1/2 cup of the pasta water, then drain the pasta and set it aside.
In a medium saucepan over medium heat, melt the unsalted butter. Once it’s melted and bubbly, pour in the heavy cream and bring the mixture to a gentle simmer.
Add the white pepper and nutmeg to the simmering cream and butter mixture. Stir well to combine, allowing the flavors to meld for about 2-3 minutes.
Gradually whisk in the freshly grated cheese until it’s completely melted and the sauce is smooth. If the sauce appears too thick, add some of the reserved pasta water to reach your desired consistency.
In a small bowl, whisk the egg yolk. To prevent the yolk from scrambling, slowly add a few tablespoons of the hot sauce to the yolk while whisking constantly.
Once the yolk is tempered, gently pour it back into the saucepan, whisking continuously until the sauce is creamy and well combined. Remove the saucepan from heat.
Add the drained pasta to the sauce, using tongs or a pasta fork to toss well, ensuring every strand is coated in the rich Alfredo sauce.
Serve the pasta immediately, garnished with additional grated cheese and freshly cracked black pepper if desired.
