Black Pepper Parmesan Pasta

Ahhh, cacio e pepe, the classic Roman pasta dish. But the cheese and pepper mix should end up creamy and sauce-like, not grainy like in the video.

Here's Kenji with a demo that does produce a sauce, albeit cheating with butter. And here's a blender cheat from Babish.

The garlic version of this is like crack. I call it crack pasta. Because you don't stop wanting more.

Seems pretty simple, but how do I cook pasta with the Finnish method?