It was a good recovery from the clump-o-rama last time when my nephew and I made cacio e pepe together over Christmas break
I made the “sauce” first — grated parm (pre-grated from freezer not fresh-grated bec I haven’t been to the store yet since I got back), water, pepper.
Then boiled the pasta, and added some of the starchy water (after letting it cool slightly) to the sauce, and mixed to form what is essentially a butter-less bechamel.
When the pasta was done, I drained it and let it cool for a few minutes —bec I’m convinced it’s the temp of the pasta that makes the cheese clump. Then transferred pasta to the bowl with the cheese sauce, stirred quickly, and added a bit more warm pasta water when it looked like it might clump, to loosen it up.
I’m convinced that the cornstarch method will be 100% less fussy, so I will try that next time. (I forgot this time.) Also want to try beurre manie as a different tweak.