How can I, a simple ex-island haole living on the mainland, make guava cake? You know what I mean-- you can get it at the supermarket bakery, it’s vaguely pink. . . Anyone recognize what I’m talking about?
Yep. I Googled and it looks like the recipes there contain anything from real guava pulp to guava juice and guava nectar/concentrate. As you’re living in California, I don’t imagine you’ll have a problem getting access to, at the very least, simple guava juice. If that fails, got some island friends to hook you up? 
I hope my sister, SparrowHawk, sees this thread. She’s haole, too, but has been living in Honolulu for the past 20 years. She’s gotta have some connections, culinary-wise, and if she doesn’t know what guava cake is, I’d be very surprised indeed.
Sis…oh, sisteeeerrrrrr!
Some recipes out there that call for guava paste. Not knowing what this looked like, I looked it up. Turns out it can either be bought online or made from scratch.
Recipes:
http://www.justfruitrecipes.com/guava/guava003.shtml
http://www.hawaii.edu/recipes/recipes.html (< This link made me homesick!)
Guava paste:
http://www.latingredients.com/conchita.asp
http://www.jewish-food.org/recipes/guavpast.htm
Brilliant, ya’ll. I actually HAVE a bunch of guava paste, as I communicated my guava-love to a friend that goes to Panama pretty frequently. I’ll give this a shot.
No, of COURSE I didn’t think to try the web. D’oh.