Put a pot of salted water on to boil. In a large bowl, combine the cheeses and black pepper; mash with just enough cold water to make a thick paste. Spread the paste evenly in the bowl.
Once the water is boiling, add the pasta. The second before it is perfectly cooked (taste it frequently once it begins to soften), use tongs to quickly transfer it to the bowl, reserving a cup or so of the cooking water. Stir vigorously to coat the pasta, adding a teaspoon or two of olive oil and a bit of the pasta cooking water to thin the sauce if necessary. The sauce should cling to the pasta and be creamy but not watery. (The secret is to stir the mostly cooked pasta quite vigorously so that its starch emulsifies with the seasonings and added water.)
Plate and dust each dish with additional pecorino and pepper. Serve immediately.
Comment: This appears to be the simplest preparation, and in their souls it is. But mastering both timing and technique requires a bit of practice. “You must get everything in balance, especially the intangibles”. Just be patient. You’ll know when you’ve arrived.
Salt to taste
1 ½ cups finely grated Pecorino Romano, plus more for dusting completed dish
1 cup finely grated Parmigiano-Reggiano
1 tablespoon ground black pepper, plus more for finishing the dish
3/4 Pound tonnarelli or other long pasta like linguine or spaghetti
Good olive oil