While you’re boiling the pasta in plenty of salted water, grate the Pecorino cheese into a large bowl. Add the pepper (freshly ground is best) and stir well.
Once the pasta is cooked, pour it into a colander but don’t strain it completely. Keep the water used to boil the pasta. Add the pasta to the cheese and pepper. Stir well to bind all the ingredients together; the cheese should melt with the heat from the pasta.
Finally, add a large spoonful of the water used to boil the pasta and stir again.