If it was someone from 长沙, I guess by saying 块子 they meant a "place."
If it was someone from 武汉, however, it should be something you eat in the restaurant.
And I've done a research, in 五一 Road in 武汉, there are really restaurants offering 块子.
块子 looks something like this:
So the translation goes: It was the first time I went to 五一 Road after I came back, and I've even seen 块子 that I recall only from childhood.
More about 块子:
Seems it's kinda like 米粉/面条, but smoother. And it's disappearing in 武汉, so I guess that's why they say they found 块子 that they remember from childhood.
Image source: http://m.dian321.com/meishi/42472.html