Theists, are you immune to being decieved?

[Esquilax]

5) Only physical processes are real; mental properties are an illusion.

Seriously: mental processes are just another set of physical ones. Considering your example, your sensory apparatus picks up the scent of cookies, and specific physical reactions, trackable within your brain, align that scent with a similar sense perception stored in your memory. Now you've been reminded of your grandma, and yet more entirely physical reactions take place within your brain, with the aim of comparing socially acceptable actions based upon this new thought in your brain, in this case, sending her a card. All the thoughts you have are just your consciousness' interpretation of the physical patchwork of heuristics and so on that have kept your lineage alive throughout the ages.

Our answer doesn't beg the question, your question just doesn't make sense. It's like you asked for the causal relationship between ice and ice; it's the same thing.