1) Bring a pan of salted water to the boil and add the spaghetti. Cook for five minutes, or around 2 minutes less than pack instructions. Scoop out 250ml of the water and set aside in a bowl.
2) While the pasta’s boiling, add black peppercorns to a very hot and dry pan and toast for a few minutes. Remove from heat and crush the peppercorns roughly.
3) Drain the pasta, keeping 200-250ml of the pasta water. Add the drained pasta, and 100ml of the pasta water, into the pan with the pepper. Toss briefly, then scatter over the cheese. Wait for the cheese to melt without stirring, and then begin to toss and stir together to prevent cheese from clumping and to make a smooth sauce. Add more pasta water if necessary to loosen sauce.
4) Once pasta is well and truly coated, serve in warm bowls with an additional sprinkling of cheese and black pepper if desired. Serve with warm, crusty bread.