Despite not being particularly bright and sometimes reckless, Julia was meticulous in her work. Maria had told her to simmer the oil for six hours, and Julia stood by the stove the entire time, never leaving it. As soon as the time was up, she stopped the fire, carefully let it cool, and strained the oil multiple times to remove all the petals. She then carried a jar of about 500 milliliters of finished oil to Maria for inspection.

Maria, who was working in Simon’s study and keeping track of the time, was just about to head to the kitchen when Julia arrived.

The essential oil made with olive oil...