And I finally tried a carlota de limon, more or less.
My limey victims. It took 8 of these to get a scant cup of juice. I zested about half of them before squeezing.
And the cans of milk, one each evaporated and sweetened condensed. I used the mixer with the whisk attachment to mix them together, which wasn't quite as easy as it sounded because of the thickness of the SCM. But eventually they combined, and I slowly poured the lime juice in while the mixer was still running. About a third or halfway through the addition, the contents of the mixer had noticeably thickened, but as I kept pouring, it thinned out. I let it keep going, hoping that it would maybe hold a bit of air and whip up, but instead it just splashed little droplets of filling everywhere. So I poured the contents into a glass measuring cup, stirred in the zest, covered it with plastic wrap, labeled it so I wouldn't confuse it with the corn soup that was in an identical glass measuring cup covered with plastic wrap, and stuck it in the fridge for several hours. My thinking was that maybe it needed a little time for the acid to better work on the milk...or maybe the chill would solidify the fat enough that I could beat it later.
When I came back, it had, in fact, solidified enough that I felt comfortable using it. So I opened my maria cookies, and assessed their size. I wanted to make individual carlotas, since they were destined to travel to some friends' house the next day. The cookies were a tad too large to fit into a regular muffin tin, but seemed to work OK in a jumbo muffin tin. So I put a paper liner into each cup (tactical error; I should have first pushed plastic wrap into the cups to help me pop the liners out later) and then distributed a cookie into the bottom of each. I added a couple of spoonfuls of glop, then another cookie, another couple of spoonfuls, etc. I think in all, each cup held four cookies with glop, plus one last cookie to top it off. The pan then got a plastic wrap topping, and a long cold rest in the freezer. I had enough glop left over to also make two custard cups, layered the same way without the plastic liner. They, too, got a plastic wrap lid and an overnight freeze.
The next day, just before we left home, I tried just flipping the whole muffin pan over with the plastic wrap still on top. Nothing budged. I wound up needing to use a plastic knife (it's a pan with a nonstick coating) to cut around each paper liner and then to lever it up and out. This part would have been much easier if I'd pushed plastic wrap down into the cup. Four of the cups then got packed into a lidded container for transport, with more plastic wrap between the layers, and the container went into a cooler of ice for the trip (an hour and a half drive, plus about another hour and a half while we ran various errands near to our friends' house). They went into the fridge while we ate lunch, and then came out.
Here's what one of the custard cup versions looks like (because nobody photographed the muffin cup version). This was about half an hour out of the freezer.
The flavor was quite bright and limey, although I think adding the microplaned zest to the goop was probably not the best way to use it, because I didn't care for the chunky texture. I also think that when I was making the goop, if I'd stopped pouring in lime juice when it visibly thickened, the goop would have been unbearably sweet. (Although a judicious addition of powdered citric acid might have helped with that.) It was certainly easy, although it needs a good bit of hands-off resting time. I don't think it would work as a roll, like the traditional chocolate water/whipped cream icebox cake is usually assembled. The idea is definitely worth playing with a bit more. Maybe chilling the evaporated milk so it would whip better would also help with the thickening?