Cook spaghetti according to package directions. Reserve about 1 cup of pasta water before draining.
While pasta is cooking, melt butter in a large skillet over medium heat.
Add minced garlic to the skillet and cook until fragrant, about 1 minute. Be careful not to burn the garlic.
Pour in the heavy cream and bring to a simmer. Stir in the grated parmesan cheese until melted and smooth.
Add the drained spaghetti to the skillet. Toss to coat with the sauce. If the sauce is too thick, add a little reserved pasta water until desired consistency is reached.
Season with salt and black pepper. Stir well.
Serve immediately, garnished with fresh parsley if desired.
Notes
This pasta is best served fresh. You can add a pinch of red pepper flakes for a little heat.