As he stacks four one-pound packs of bucatini on Cassinelli’s compact counter, Giovanni Cali all but apologizes for his pasta purchase.

“I can make it at home,” he said. “But I don’t want to.”

It’s as difficult to find a store that sells bucatini, which looks like spaghetti with a hole in the center, as it is to make it. And this is why Mr. Cali has been a Cassinelli customer for nearly 50 years.

He is also a fan of the freshness. Each week, Cassinelli makes 3,000 to 4,000 pounds of pasta on site, right in the shop for all to see.