According to the Star Trek Cookbook, the pie was pumpkin pie mix colored with fruit juice. Beets were used to create the "hairy" appearance. Here is a picture of the rokeg blood pie from "A Matter of Honor" (TNG).

This particular version should probably be the equivalent to pumpkin or sweet potato pie filling and, thus, a desert.
The rokeg blood pie from the Star Trek: Klingon PC game looked like this:

That could very well be a simple open top cherry pie.
Finally, there is this version

This appears to be a gelatin mold on a gram cracker crust.