You need the following after unlocking the spit from analyzing items, like peblet, dry grass chunk
4x Pebblet
4x Sprig
3x Dry Grass Chunk
It is in the crafting menu place it, and then you need meat, aphid ,meat, gnat etc and cook on the spit.
Edit:
**Seems only Aphids work for some people, I did it with gnat meat**