Fill a large pot with water, season generously with salt, and bring it to a boil. Add pasta and cook according to package instructions until al dente, about 8-10 minutes. Reserve a cup of pasta water, then drain and set aside.

In a skillet over medium heat, melt butter. Add minced garlic and sauté for 1-2 minutes until fragrant.

Pour in heavy cream and stir to combine. Heat through for 3-4 minutes until thickened.

Reduce heat to low and whisk in parmesan cheese until melted and creamy. Season with salt and pepper.

Add the drained pasta to the sauce, tossing to coat. Adjust sauce thickness with reserved pasta water if needed.

Stir in any optional ingredients like spinach or chicken, cooking for an additional minute.

Serve immediately, garnished with extra parmesan cheese and herbs if desired.