Bring the water to a rolling boil, and then add a tablespoon of salt. Do not use much water to cook the spaghetti because you have to reserve as much starch as you can in order to make your space silky and creamy. Fill the stockpot halfway full (normally you would fill it 3/4);
Cook the spaghetti according to the instructions on the package. Stir occasionally so the pasta doesn’t stick together;
Grate the Pecorino cheese and coarsely grate the peppercorns;
Take half of the crushed peppercorns and toast them over medium-low heat. Stir the peppercorns with a wooden spoon so they don’t burn;
Cooking the pasta, drain it and save the pasta water. Pour the pasta into the skillet with the peppercorns and go on cooking it with a scoop of the pasta water tossing it with tongs until done;
Prepare the sauce with the Pecorino just before serving to keep it silky and smooth;
Prepare the following sauce with the Pecorino cheese just before serving in order to keep it silky and smooth. Pour half of the grated Pecorino cheese into a bowl, add about a scoop of pasta cooking liquid and whisk it quickly until it is as white as whipped cream. Add another scoop of pasta cooking liquid and the remaining Pecorino. Whisk it vigorously until the cheese has completely melted and is smooth. If the cream gets too thick, add a splash of water, but be careful; it must not be too liquidy. The temperature of the water will melt the cheese. The more mature the Pecorino is, the hotter the water must be;
If the Pecorino sauce isn’t hot enough, put it in the skillet with the cooked pasta for a few minutes. The sauce and pasta should be at the same temperature;
When the pasta is done, remove the skillet from the heat and add the Pecorino sauce. Toss the pasta with tongs until it is evenly coated;
Place the pasta in serving bowls and garnish each with some more freshly grated Pecorino cheese and black pepper.