Cacio e Pepe

Lumping happens when cheese is added too fast or to heat that's too high; always add cheese while tossing off-heat and in small amounts. Oiliness means the emulsion broke, usually from too much heat—stir in a tablespoon of cold pasta water and toss off heat to fix it.

This dish cannot be made ahead—it must be eaten the moment it is finished or the sauce breaks. Cook it in batches rather than doubling, making one 4-serving portion at a time.

Buy a block of Pecorino Romano (not the pre-grated version, which contains anti-caking powder that prevents melting) and grate it fine on a microplane right before cooking.

Parmesan is too mild and lacks the sharp saltiness that defines cacio e pepe; if you must substitute, use half Parmesan and half Pecorino, though the dish will be noticeably different.

Two tablespoons of freshly cracked pepper (not pre-ground) is the standard; this seems like a lot but is correct—crack it yourself so it stays bold and aromatic rather than dusty.

Authentic cacio e pepe uses only pasta water, cheese, and pepper; adding butter or cream changes the dish entirely. If your sauce breaks, fix it by adding cold pasta water and tossing off heat, not by adding fat.