As Mr Denham’s survey of Hänsel und Gretel recordings is so exhaustive I would love him to include the earliest complete recording, which also was the first in German to be issued on LPs. That probably was in 1952 on Urania URLP 212 as part of a deal with radio stations in West Germany. At the time few knew that it is an example of war-time German tape technology, sounding good enough for Urania to make a stereo transcription of it in the 1960s. The date now commonly cited is 25 April 1944 in Berlin. If you subscribe to the web magazine Liner-Notes (you should: https://liner-notes-magazine.com/) you will find page 161 of the Fall issue (released this month) devoted to it, as part of a celebration of Urania’s cover artist Siegmund Forst.
In 1952 the main “draw” was Gretel, Erna Berger who had just finished a belated two-season career at the Met. She was born in 1900 but retained her young-girl voice throughout the 1950s. For me she remains the perfect Gretel. The whole performance under Arthur Rother is well worth hearing and has been available on various CD labels and Youtube. What should have made 1952 listeners suspicious about its date is the Witch, Margarethe Arndt-Ober who was a leading artist with the Met 1913–16!
Youtube also has a 1937 Met performance. But maybe the most “authentic” historical performance of all is Polydor’s Kurzoper from 1929 on eight very long 78 sides, which is also on Youtube and was on Pearl GEM 0155. It is one of a series of operas adapted mercilessly for home use by Hermann Weigert (later Astrid Varnay’s husband) who also conducts. He reduced the first and second acts to not-quite ten minutes each and the third act to twice that by retaining glimpses of key numbers and a minimum of in-between stretches. Somehow he created a coherent narrative without too disturbing clashes of musical keys. We really get a good impression of a possible Berlin cast, with a few singers who were locally famous at the time. Like in all Kurzopern we hear them interact more than in contemporaneous recordings of isolated numbers.