As someone else posted has anyone tried this without cinnamon? My son is not a cinnamon chocolate fan?

And kudos to your son for his sturdy good sense.

Hello! Yes, you can absolutely leave out the cinnamon. This cake came about when I was pregnant with my second son, and on a bit of a Mexican-style hot chocolate bender. As I said to someone else, you can add a bit of espresso powder if you'd like, but the replacement isn't necessary. Best of luck!

I've not tried it without the cinnamon, but there is a lot of flavor here from the walnuts, chocolate, vanilla. I think it would be fine without cinnamon. No need to substitute another spice, but if you want, I would go for nutmeg or cardamon, very small amount (pinch only), if he likes one of those.