Raisins were steeped for the Messenger of Allah (ﷺ) and then dried dates were infused in them, or dried dates were steeped and then raisins were infused in them.
Sunan Abi Dawud Book 27, Hadith 39
← Previous Hadith Kabshah, daughter of AbuMaryam, asked Umm Salamah (Allah be pleased with her): What did the Prophet (ﷺ) prohibit? She replied: He forbade us to boil dates so much so that the kernels are spoiled, and to mix raisins and dried dates.

Sunan Abi Dawud Book 27, Hadith 38 Next Hadith → Safiyyah, daughter of Atiyyah, said: I entered upon Aisha with some women of AbdulQays, and asked her about mixing dried dates and raisins (for drink). She replied: I used to take a handful of dried dates and a handful or raisins and put them in a vessel, and then crush them (and soak in water). Then I would give it to the Prophet (ﷺ) to drink.

Sunan Abi Dawud Book 27, Hadith 40