Alfajores Con Cajeta (Vanilla Shortbread With Goat's-Milk Toffee) Recipe

When you live with the knowledge that a jar of seductively rich homemade cajeta is never more than an hour away, your every thought bends to its service. You imagine it over everything from French toast to ice cream, and how its notes of butterscotch and toffee would improve life across the board.

Yet, of every possible application for Mexico's famed goat's-milk "caramel," I can think of none more perfect than an alfajor. These little sandwich cookies aren't Mexican per se, but a beloved tradition across much of Latin America, where buttery shortbread serves as a vehicle for dulce de leche in all its regional forms.

If you've never had the pleasure, envision a French sable filled with a spoonful of salted caramel, rich and chewy in turn, then multiply your expectations by a factor of 10. Where sables are crisp, alfajores are tender; where caramel is bitter, dulce is sweet; where other cookies crumble, "Alfies" melt away.

Their uniquely fragile texture comes from cornstarch, which reduces the overall need for flour in the dough, minimizing gluten development for a crisp but powder-soft shortbread. Instead of crunching or snapping, alfajores yield to the slightest touch, preventing their creamy cargo from squishing out the sides.

Of course, cornstarch can't help but taste starchy, giving alfajores a subtle chalkiness you either learn to love or learn to ignore. The problem is that cornstarch is fairly resilient, able to withstand temperatures up to 212°F (100°C)—well above the internal temperature of the cookies as they bake. Tapioca starch, derived from cassava root, is blessed with no such strength.

As I discovered with my lemon meltaways, another cornstarch cookie, tapioca starch performs identically in a one-to-one swap, except that it begins to break down in the oven as the cookies approach (and surpass) 140°F (60°C). Its individual granules then swell and burst, rendering them all but imperceptible to the human tongue. In short, tapioca starch does its job, binding the dough in the absence of flour, then fades away, leaving nothing but a sense of buttery richness. And, for those concerned about highfalutin ingredients encroaching on South American cuisine, rest easy in the knowledge that cassava is native to Brazil.

With the shortbread squared away, it all comes down to your choice of filling. For most, the answer is dulce de leche, or its ultra-thick counterpart, manjar. But, when push comes to shove, cajeta will always be near and dear to my heart. Not only is it faster and easier to prepare, it's more flavorful than dulce de leche's wildest dream.

That's because neither dulce nor cajeta is a proper caramel, or else their flavor would be on equal footing. These Latin American specialties derive their signature color, flavor, and aroma not from caramelized sugar, but from the Maillard browning of amino acids—lysine and cysteine in particular. That's where things get interesting because, compared to cow's milk (the foundation of dulce de leche), goat's milk has two times more lysine and five times more cysteine, fueling a more flavorful transformation en route to cajeta. If you like, you can check out the full breakdown of their differences in my article here.

With the whys of my recipe laid bare, the hows are crazy-simple: Pulse all the dry ingredients with butter in the bowl of a food processor, crack in a couple of egg yolks, and you're done. Like stirring ingredients together in the days of yore, a food processor minimizes the introduction of air into the dough, for cutout cookies that bake up slim, not puffy. Because you can process cold butter straight from the fridge, the dough stays cool as well, which means you don't have to chill it down. As it forms a ball, you're ready to rock and roll.

Unlike simple shortbread and pâte brisée, alfajores are enriched with egg yolks, making the dough too supple and smooth to crack or tear. It's a breeze to handle, and my favorite trick is to roll it out with powdered sugar instead of flour, ensuring every cookie turns out sweet and tender (particularly those made after gathering up and re-rolling the scraps).

The alfajores bake only until firm and pale gold around the edges, keeping their flavor light rather than nutty, which is where the cajeta shines. If you've prepared a batch in advance, you can assemble the alfajores as soon as the cookies are cool, but there's no rush if you'd prefer to whip up some on the fly.

With my recipe, a single batch will make either just enough or twice as much cajeta as you need. Truth be told, a quarter ounce of filling each is perfect for the alfajores, but what's perfect for me is using up every last drop.

You can dollop each portion with a spoon, but I find the process a little faster with a pastry bag. It's a matter of personal preference, so don't feel compelled to follow my lead—advice that extends to the cajeta itself. While I like it soft and gooey, you may want to cook it down to a thick, spreadable paste. There's no right or wrong answer here!

However it's prepared, aim to keep the cajeta within the very center of the alfajores. It'll spread plenty on its own when sandwiched with the remaining wafers.

Once assembled, Alfies are traditionally finished with a dusting of powdered sugar to highlight their clean, geometric shape. Not too long ago, I would have skipped this step altogether, but, having discovered the mellow flavor of organic powdered sugar, I'm more than happy to oblige. (Long story short, organic powdered sugar starts with raw cane sugar, complex and mellow with the flavor of molasses, which tames its perceived sweetness.)

As a final touch, alfajores are often rolled on their edges in shredded coconut, perhaps to seal in their filling. If you've got access to the fresh stuff and a traditional grater, by all means, go to town! But, considering how bland and dry (or creepily moist) bagged coconut can be, it's a garnish I'm keen to avoid.

Besides, having tweaked the recipe to ensure the shortbread's clean-melting texture, I'm eager to enjoy alfajores in their purest, simplest form.

With their elegant shape and sophisticated flavor, alfajores offer a certain amount of swagger when it comes to dinner-party desserts, and homemade cajeta? Lifetime bragging rights! But despite their fancy air, alfajores are simple enough to serve with afternoon coffee for a group of friends, where...oh, man, who am I kidding? Alfajores aren't the sort of cookie to inspire generosity. They're the sort of buttery luxury you'd rather hide away than share.