I have always loved acorns since I can remember. They come in all different sizes too, and are fun to walk on thru the woods. The wildlife depends on them for food, but we can eat them too.
Back in my vegetarian days in the 70's I was also into learning about wild edibles. I had gathered lots of acorns thru those years and processed them into a flour. Allot of work, but the food is there if needed.
I found this article online which is excellent in explaining the process of gathering the acorns to making into flour here and here too
Spiced Pickled Acorns recipe here
From Redhawk's Lodge here more information and recipes
Recipe for cake here
Acorn bread here
I found this photo using acorn flour: