This sauce is sufficient for 12 to 16 ounces of pasta. It’s made to shine when there are few additional ingredients but, of course, you could use it as an ingredient in other Italian dishes: soups and stews, ragus and lasagne, to name a few.
Reduce heat and simmer tomatoes, partially covered, for 7 to 8 minutes, until they have softened and collapsed. Stir in parsley, butter and red pepper until butter melts.
Taste sauce and add more salt or pepper as needed. If the sauce tastes too acidic, add a little sugar.
• San Marzano refers to a zone around Naples known for its superlative plum tomatoes. But the term also refers to the variety of tomato, which might be grown elsewhere, such as in California. I favor tomatoes grown in Italy but am open to any tomatoes grown and canned with care. Cento, Anna, La Regina and Vantia are brands I’ve used and liked.