Here's the secret: between the graham cracker crust and the key lime filling, there is a layer of caramel sauce and toasted pecans. Ohmygosh. It is serious, people. Seriously good.
Because I'm catching up on my posts from China and am short on time, I'm not going to rewrite the recipe here. If you want to make it (and trust me, you want to make it), just click on this link from Southern Living:
The only remark I would have about it is that I've made it twice now, and the first time was better. The only difference was that the first time I made it, I was lucky enough to score a bottle of fresh key lime juice, and managed to avoid squeezing 25 tiny key limes myself. The second time, I couldn't find the pre-made stuff, so I recruited my loving boyfriend to squeeze said limes for me. The resulting filling was, for some reason, much more bitter than the first time I made it. So word to the wise: Take the short cut on this one, and use the pre-made juice if you can find it. If not, maybe go easier on the amount of zest you use.