To begin, grab that stockpot, fill it with water, and heavily salt it. The water needs to be SALTY. Maybe not quite like the ocean, but enough to know you have some good salinity in that water. This is the only way to get flavor into the noodle itself.
Bring the salted water to a boil.
Once the water comes to a boil, carefully add your pasta of choice and cook it according to the package instructions.
The Sauce
When the pasta is almost finished cooking, add the butter to a large skillet on low heat. Let that melt. Have the parmesan cheese, kosher salt, and fresh ground pepper at the ready and close by.
Add the strained pasta to the large skillet.
Vigorously stir the pasta in with the butter. Add the pasta water along with the grated parmesan cheese and fresh ground pepper. Keep stirring. If you think you need a little more water, add it. This will only help the sauce to become more silky and it will absorb into the noodles.
Taste for salt and if you think it needs a little more, add some.
Enjoy!
Notes
I recommend keeping a little extra pasta water to the side just in case you need it. Everyone is gonna use a different pasta, probably add more cheese, and maybe even more butter, so the exact water amount will differ. Just don't throw out that water until you're done!