Authentic spaghetti cacio e pepe
Switch off the heat completely and make sure that at least one headed cooking water in the pan where you cooked the pasta. If the spaghetti becomes too sticky, add a trowel of the reserved noodle water (it should be hot but no longer cooking, as high heat can cause the cheese to split and clump) and mix. The cheese, the cooking water and the thickness will all stay together to prepare a creamy, emulsified sauce.