The Danish letter (glyph) å in the word påskefred is a problem when searching.
About the letter Å (å in lower case) see https://en.wikipedia.org/wiki/%C3%85 = https://en.wikipedia.org/wiki/Å

Until 1948 the letter was written as aa.
Searching for paaskefred with the old orthography may give other results than searching for påskefred.

A search for: Paaskefred verdenskrig
(where verdenskrig = world war) reveals the book “Krigerliv og religiøsitet” (= Warrior life and religiosity) written by Eivind Berggrav-Jensen, published by “Steen’ske Bogtrykkeri og Forlag” in Kristiania, 1915:
https://www.kb.dk/e-mat/ww1/130019373771.pdf
The city Kristiania is the capital of Norway, since 1925 denoted Oslo.

Page 51 in this book, written in Norwegian Bokmål:
“Det tredje tilfælde er fra østfronten. Det er kanske typisk for den større rolle paasken endnu spiller for russerne, at det var disse som bad om at faa paaskefreden anerkjendt. Brevet er fra musikeren Willy Gallaun rettet til fru professor S. i Marburg. Det er datert 6te april i nærheten av Lodz:”

“Rent utrolig vil De sikkert finde følgende beretning. Jeg hadde selv aldrig i verden trodd at noget saadant var mulig, hvis jeg ikke hadde deltat i det selv. Første paaskedag kom vi til denne stilling i nærheten av Lodz. De som vi skulde avløse, fortalte os at russerne hadde været over og bedt om at der ikke skulde bli skutt i paasken. Ønsket var ogsaa blit opfyldt. Nu kom russerne
bortover til os, helt hen til pigtraadforhindringen. Vi maatte op og gaa dem imøte forat de ikke skulde komme helt ned i vor skyttergrav; det gik jo ikke an. De kan ikke tænke Dem hvorledes russerne opførte sig, ganske som barn. De saa ynkelige ut i sine traser; men sult var der ikke tale om. De hadde med sig brød, smør, skinke, sukker og tobak for at bytte med os. Vi hadde vore langpiper i munden, og da de fik se dem, blev de saa begeistret at slik en vilde de alle sammen ha. – – – En av officerene vore tok et fotografi av gruppen. Der stod tyskere, østerrikere og russere mellem hverandre.”

I sætningen / in the sentence ‘De saa ynkelige ut i sine traser’ forstår jeg ikke ordet ‘traser’ / I do not understand the word ‘traser’.

The book is from 1915, so the letter / testimony is from Easter 1915, where date of Easter (Easter Sunday) was April 4 in the Gregorian calendar / Western Christianity.

I have not been able to find information about the writer Willy Gallaun. The story from the letter must have been written in German. If we had had the text in the original language it might have been possible to find it on the net.

The author of the book, Eivind Berggrav, was a Norwegian Lutheran bishop. The book ‘Krigerliv og Religiøsitet’ has been republished in 2016.

About Berggrav and his book:
http://pacem.no/2003/krigerliv-og-religiositet/
From the English Summary: “Eivind Berggrav, Bishop in Oslo and leader of the church confronting Nazism during the Second World War, wrote a book called Krigerliv og religiøsitet in 1915, which was a great success. The book deals with his experiences during a journey to Germany in 1915 as a war correspondent.”

As a young theologian Berggrav was a war correspondent in Germany in July and August 1915 for the newspaper Morgenbladet, and he visited the front in Belgium and France in August 1915.

– – –
The following is from an earlier search.

https://greatwar-1914.tumblr.com/post/142580205711/april-10-1916-easter-truce-between-austrians
“Orthodox Easter fell on April 10, 1916, Though Russian troops were embroiled in heavy fighting in Belarus, those facing the Austro-Hungarian Army made a truce with their enemies for Easter. Men from four Russian regiments crossed the lines to the other side, …”

https://www.tes.com/teaching-resource/easter-truce-1916-ww1-11523562
This is less known story about a truce between Austria-Hungary and Russian army on Eastern front in 1916. It is a lovely addition to the Christmas Truce from 1914 on the Western Front.

Download the file “WW1-Eastern-Truce.pptx” (via a zip-file). The file can be opened by ‘PPTX Viewer’ from Microsoft.

“Friedrich Kohn was serving as a medical officer with a Hungarian regiment in Galicia, …”
So same testimony as quoted in
https://www.gatewaysfww.org.uk/news/easter-truce-1916
mentioned in my previous comment. But in the pptx-file supplemented with illustrations.

Hello Daniel !
I have posted a comment. It contains links and therefore the comment is awaiting approval. Hopefully it will be approved and made visible later tonight or early tomorrow.
I wish you good luck with your project.
In which country do you live ?
Best regards
Erik
Copenhagen, Denmark

“For Russian troops the Easter festival was of greater importance than Christmas. Therefore this is a particularly fitting time to dig out the testimony of someone who witnessed an Easter truce on the Eastern Front in 1916. Friedrich Kohn was serving as a medical officer with a Hungarian regiment in Galicia, where … In 1981, in a letter to Malcolm Brown and Shirley Seaton as they were working on material for their book and television programme Peace in No Man’s Land, Kohn recalled the events of Easter Day 1916:
The winter of 1915-16 was very severe … Then suddenly on Easter Sunday, about 5 o’clock in the morning, about twenty Russians came out of their trenches, waving white flags, carrying no weapons, but baskets and bottles. …”

“Friedrich Kohn’s words taken from Malcolm Brown & Shirley Seaton, Peace in No Man’s Land (Pan, 1984)”.

Same story: https://blogs.kent.ac.uk/gateways/tag/easter-truce/

– – –
I doubt that you can find more about påskefred (Easter truce) in 1916 at the present website DenStoreKrig1914-1918.dk.

(The word truce in Danish: våbenstilstand. (Våben = weapons)).
I have tried to search for: Påskefred site:denstorekrig1914-1918.dk
The report from Chr. Ohrt is the only relevant answer.

About Chr. Ohrt:
Christian Nicolai Ohrt
https://denstorekrig1914-1918.dk/soenderjyder-oversigt/soenderjyder-o/ohrt-christian-nicolai-1873-1958/

– – –
The word truce in German (auf Deutsch): Waffenstillstand

Search for: Ostern Waffenstillstand 1916
The word Osterfrieden (‘Easter peace’) can also be used.

https://d-nb.info/1138280631/34
Arnold Gieseke
Die “Sammlung Kriegsberichte (1. Weltkrieg)”
Feldpostbriefe
5.7.2 Osterfrieden 1915: “Wir sollten wiederkommen und Wuttky mitbringen”

“Der Oberjäger Beckmann, von Beruf Tischler, aus Eggeberg bei Halle i/W. berichtet seinem Heimatpfarrer Nase von einem Ereignis, welches man als “Osterfrieden 1915 an der Ostfront“ bezeichnen könnte.”

“Es kommt zu einer friedlichen Begegnung der gegnerischen Soldaten zu Ostern, das zufällig am selben Tag in der russisch orthodoxen Kirche und der evangelischen bzw. katholischen Kirche stattfindet. Eine überaus menschliche Begegnung mit dem Austausch von Geschenken und vermutlich auch Diskussionen über den Krieg.”

“Die Russen haben in diesem Jahre mit uns zusammen Ostern. Die Russen werden sehr freundlich zu uns, so haben sie uns gestern Osterkuchen und Ostereier herüber geschickt zur Feldwache. Dann sind 3 Jäger von uns herüber gegangen, mit einem Paketchen Zigarren, Zigaretten und Kognak und sind von 3 Russen empfangen worden. Haben Zigaretten ausgetauscht und haben sich lange Zeit unterhalten über die Kriegslage usw.. […] Wir sollten wiederkommen und Wuttky mitbringen, sie wollten gern bezahlen.”

Source / Quelle: Beckmann: Abschrift eines Briefes vom 5.4.1915 aus Rorcivuz, Sammlung Kriegsberichte.

(Wuttky ??: Google / the internet does not offer an explanation).

http://m-kummer.de/legion.pdf
Diplomarbeit. Verfasser Gabriel Župčan. Universität Wien.
“Der tschechische Soldat František Křížek vom IR 56 berichtet über einen Osterfrieden zu Ostern 1916, als die Russen ihr Artilleriebombardement eingestellt haben. Dies zeugt von einem besonderen Verständnis für die andere Seite, da das russischorthodoxe Osterfest vom Datum her nicht mit dem katholischen bzw. reformierten übereinstimmt. Die Soldaten beider Kriegsparteien treffen sich im sogenannten Niemandsland zwischen den Gräben, tauschen Waren untereinander und umarmen sich gegenseitig. Dies geht den ganzen Tag lang, bis am Abend …”

Hello Daniel
Thx for your comment 🙂 The short answer is: Maybe! Under “litterature” you will find a lot of scanned material, mostly memoirs from soldiers from North Schleswig in the german army 1914-1918. You might find further mentions of the easter truce there. The danish word for easter is “påske”.
best regards
René