Mince the garlic and grate the Parmesan cheese; measure out all ingredients for quick assembly.
In a large skillet over medium heat, melt the butter completely without browning it.
Add the minced garlic and sauté for 1 minute, stirring constantly to avoid burning.
Pour in the heavy cream, stir to combine, and bring to a gentle simmer; cook for 2-3 minutes, stirring occasionally, until slightly thickened.
Reduce heat to low and gradually whisk in the grated Parmesan a handful at a time until fully melted and smooth.
Season with salt, pepper, and optional nutmeg; stir well and remove from heat. (If too thick, add a splash of pasta water.)
Serve immediately over pasta or as desired.