Go to Edgeville. The house west of the bank is Evil Dave's mother's house. Talk to her and ask her either question. Then, climb down the trapdoor. You will see that Evil Dave has gotten into summoning demons as well. However, they are hellrats, the weakest form of demon ever. Talk to him, and ask him what he ate, saying he must tell you "because the magic requires it". He'll eventually tell you that it was a perfectly spicy evil stew, like the ones his mother makes. Talk to Doris (Dave's mother) again. She will tell you that the hell rats stole all of the spices.