Take a look at the Airbus A320 FCOM Duyentranvan
In particular FCOM 1.24.20 p4 Electrical Controls and Indicators
Here is a quote from the manual :
The main galley, the in-seat power supply and the IFE system are
automatically shed :
– In flight : when only one generator is operating.
Therefore, when both engines stop, this means both generators stop. Engine failure is relevant here.
Even if the APU is running, the galley will be shed as only 1 generator is operating.
Therefore, unfortunately, the pax
CAN NOT enjoy a coffee when the 2 engine stop turning.