Guava Bars Recipe

I made these in response to a request from a Colombian coworker for "something guava". Guava paste can usually be found in the international aisle of well-stocked grocery stores. You may find it in a wrapped bar as opposed to a large flat tin; I find that the canned product is better-tasting and more attractively colored than the stuff in the bar, but use what you can find."
From the Muffin Goddess.