Interesting topic, I couldn’t find much useful in english about eastern German food. Being from the west I only had a small glimpse at Eastern dishes and food traditions when dating a saxonian girl for a few years. (She did not have a saxonian accent by the way, which is widely considered the least sexy German accent)
You can see some eastern European or even russian influences on some dishes (explainable probably by the cold war allegiance to the Soviet Union), while others seem to be simply very regional. In (formerly) very poor areas like the Ore Mountains for example, super simple peasant dishes like potatoes with quark and flax seed oil seen to have survived. Many dishes also seem to have in common that they reflect the often experienced lack of ingredients, so people had to improvise.
One GDR favourite was Soljanka, some kind of eastern style stew. Great!
Another favourite of mine was Sunday roast with potato dumplings. This tradition I feel was not very common in the parts of Germany where I grew up, but seemingly especially well observed for example in the relatively wealthy Vogtland region.