While the water is boiling, prepare the cheese sauce. In a bowl, combine 1 oz Pecorino Romano for every 3.5 oz of pasta (adjust to taste), a little pasta cooking water, and some black pepper.

Whisk everything together until it forms a creamy sauce.

Mix for a couple of minutes over low heat. If the sauce gets too thick, add more reserved pasta water.

Before draining the pasta, save some of the cooking water. Add the drained spaghetti to a skillet and mix in the cheese sauce you prepared earlier.