I don't know of a commercial product like that, but if you Google for 'power outage logger arduino' you'll find a number of projects that may be useful.
But if I were doing this, I would look at a 3.3V 8MHz Arduino Pro Mini with LED removed, powered by an 18650 battery backed up by a TP4056 USB charger, and the DS3231 RTC module known as the ZS-042, which also has a 4KB EEPROM on it. I don't think I would bother with a display. The input voltage to the TP4056 from a wall wart could be divided down to 3.3V, and used to trigger an interrupt on the sleeping Pro Mini - falling edge to record an outage, and rising edge to record power restoration. On each interrupt, the Pro Mini would read the current time from the RTC, and save an entry to the EEPROM. Then it would go back to sleep. Actually, a much smaller battery than the 18650 would probably do fine. The processor will sleep at something less than a microamp, and the RTC will have its own coin cell. it will probably all last for years.
Then to read out the data, your code would just read the contents of the EEPROM and export it to serial output, and any terminal program listening would save the data to a file.
One thing you would have to figure out is how to handle an outage that isn't clean, but has flutter. Maybe a transition isn't counted unless it lasts at least one minute.