Grilled Peaches and Pound Cake With Cider Vinegar Caramel Sauce

During high school, Labor Day weekend always felt like the last hurrah of summer. I remember sitting at my classroom desk days later, longing for the warmer months. The funny thing is, it was still hot as hell outside. Don't make the same mistake as my teenage self, thinking summer has ended just because the vacations have. We don't have to swap sandals for sweaters yet.

My birthday is the week before Labor Day, and growing up (and even now) many of my friends are away. But these days, I'm never sad for friendless birthdays; they just mean I don't have to share my cake. One year, about a decade ago, my wife made me Karen Demasco's peach upside-down cake for my birthday, a recipe she found in New York Magazine. Peach is my summer fruit of choice,* and the recipe's soft buttery cake gets drenched in caramel and is topped with the chewy, gooey morsels that form on the bottom of the pan. I've requested it every year since.

I date this love back to the summer of 1995, when, as some of you may recall, a band called the Presidents of the United States of America came out with their hit radio single, "Peaches". The song's archetypal four-bar structure was common to many alternative-rock hits at that time, but it created an undeniable earworm. While most of the summertime anthems of that era vanished each year to free up space for the next one, this one stuck with me for some reason, and, along with it, the peach became my lifelong fruit of choice.

But my birthday is the only time she's willing to make it, which means I need to find other ways to scratch that itch. Recently, I thought of attempting a rendition of it on the grill. My initial idea was to bake a cake in a pan over the coals. This was an idea that Serious Eats's resident pastry expert Stella Parks refused to support (politely, of course, because she's a true southerner). I next proposed we make sponge cakes using the radiant heat of extinguished coals; this too was delicately shot down. Stella's objection was that the highly variable temperature of a grill would make it near impossible to write a recipe that other cooks could successfully repeat. And so, together, we sought solutions, a way to replicate the flavors of that celebratory peach cake without having to work too hard (in honor of the last weeks of summer, of course).

Stella brilliantly suggested I use pound cake as a base—either store bought or homemade—because it's something you can buy or bake days in advance; it can even be frozen, if need be. And it will toast up quickly and beautifully on the grill. It's a great trick for any fruit-based summer desserts, it even works as a cheater's strawberry shortcake.

I knew I wanted to grill the peaches as well. Part of the goal is to caramelize the existing sugars in the fruit, but I like to augment that effect by dipping the cut face of each peach half in sugar, which melts and deepens in flavor as it cooks over the coals, while forming a candied surface that helps trap some of the juices in the fruit even as it becomes meltingly tender.

For the grilled version of my birthday cake's goldmine of caramel, I looked for a little lift from—you guessed it—vinegar. I combine apple cider vinegar with sugar to make a sweet and sour gastrique (the French term for a sweet-sour sauce made from caramel and vinegar), turning it velvety by adding chunks of butter. The fruitiness of apple cider vinegar makes it a no-brainer for fruit-based desserts. A word on cooking vinegar over a flame: The vapors of boiling vinegar can knock you off your feet, so stand back and avoid inhaling deeply right over it. Your nasal passages will thank you.

When assembled, the grilled slice of pound cake is crisp and buttery, the peach is sweet and smoky, the caramel is compellingly acidic and rich, while a dollop of cold whipped cream crowns the dish. If this is the flavor summit of summer's end, it's worth waiting for. I'll happily savor it all year long.