Cook spaghetti according to package directions. Make sure to reserve 1 cup pasta water and do not rinse the pasta when you strain it. This helps with the texture.
Meanwhile, put pepper in a saute pan and toast over low heat for about 1 minute to get it fragrant. Add the broth and drizzle of oil (if using) and heat over medium low heat until it starts to simmer.
Add the pasta water and bring to a simmer.
Whisk in the cheese to make a slurry.
Add in the pasta and mix well to combine. Taste and add more salt if needed.
Serve with more Parmesan if you prefer!
Notes
Traditionally this dish uses Pecorino Romano cheese. You can use this if you aren’t needing this to be dairy free.