Bring a large pot of salted water to a boil. Add the spaghetti and cook according to package instructions until al dente.

Reserve 1 cup of pasta water, then drain the pasta in a colander.

In a skillet, melt 1/4 cup of butter over medium heat. Add minced garlic and sauté for about 1 minute until fragrant.

Add the cooked pasta to the skillet along with the remaining butter, parsley, and red pepper flakes. Toss to combine.

If the pasta seems dry, add reserved pasta water a little at a time until desired consistency is reached.

Season with salt and black pepper to taste.

Serve immediately, garnished with additional parsley if desired.