The fat is necessary for a good result. Either from nut butter or oil. I give both options in the recipe and either can be used. Maybe you used oil the first time? If it bothers you though use oil, cashew or almond butter instead. Peanut butter has a stronger flavour so its flavour can come through. It complements the other flavours though so shouldn't be a problem unless you don't really like peanut butter.

Thank you- I really appreciate your reply! I wouldn't have guessed that about sugar being so important to the structure, so I'm glad I asked. I think I will reduce it as you suggested and mix in some sun dried tomatoes, garlic, rosemary, & thyme. Maybe top w some rosemary butter? I'll let you know how it turns out!

Sugar is really important for structure in cakes so it might not turn out quite as well if you remove it. Usually you can reduce it by about a third with not too much difference. I think in this you might get away with halving it as it's quite a dense cake anyway. You can safely add any mix-ins you like though and it will be fine. Have fun!

I'm really pleased you enjoyed it Helene!

The sorghum is crucial for the texture and flavour in this recipe so I don't recommend using a substitute. It really is the best flour to use for this. If you use something else it won't turn out as good and will change the taste and texture. Also if you use another gluten-free flour you would need to introduce a starch of some kind to stop it crumbling which would also mean changing the liquid quantity etc. It wouldn't just be a straightforward swap. If you aren't gluten-free spelt flour might work but I haven't tested it that way.