Cheese and Black Pepper Pasta (Cacio e Pepe)

Simple and delicious. No explaining it.
Use Pecorino or Parmesan Reggiano, or both. I prefer Parmesan. The recipe can be halved for a solo meal. I don't know any other recipe where fresh ground black pepper is such a star.

Ingredients:
3/4 pound spaghetti or other thick pasta
One to one and a half cups finely grated Pecorino Romano or Parmesan Reggiano cheese, about 3 oz.
2 teaspoons freshly ground pepper
2 tablespoons olive oil
1/2 cup of water and a teaspoon of cornstarch

Preparation:
Mix the ground pepper with the finely grated cheese. (Here is the best grater I have found.)
While your pasta is cooking, in a small non stick saucepan mix the cornstarch with a little of the water to make a slurry, then add the rest of the water, then heat and stir the mixture until it thickens (the water will turn from cloudy to clear). Add the olive oil. You can turn the heat off until you are ready to go.
A few minutes before the pasta is done, reheat the cornstarch mixture and slowly add the cheese and pepper while stirring until you have a sauce. Keep a low flame under the sauce while you drain the cooked pasta and quickly put it  back in the pasta pot.  Mix in the cheese while stirring the pasta. Serve right away in warmed bowls.