As the daughter of an extroverted Southern lady, I attended more than my fair share of church socials, bridal luncheons, housewarmings, and baby showers, each a blur of pastel crepe paper and plastic party plates. While the specifics of any given menu were generally potluck, I could always count on two things: a glittering bowl of rainbow sherbet punch, and a tray of lemon meltaways.
It was the buttery shortbread that made these dress-up events worth attending, my chance to mainline powdered sugar for an afternoon while Mom looked the other way. They tasted like a glass of lemonade magicked into a snackable form, magic being the operative term, because lemon meltaways taste preternaturally light.
Instead of having a crisp or crunchy texture, meltaways disintegrate in a shower of sandy crumbs that evaporate off your tongue like cotton candy, leaving nothing but a lemony aroma in their wake. Well, that and enough powdered sugar down the front of your shirt to count as a Tony Montana cosplay.
With lemon meltaways, powdered sugar isn't just a finishing touch but an integral part of the dough. Along with a generous helping of cornstarch, it reduces the overall need for flour, weakening the cookie's structure to create a uniquely fragile crumb. Like any sort of dark art, the magic of cornstarch comes at a price—a case of cotton mouth something fierce.
As a kid, I never seemed to mind (maybe because of all that rainbow sherbet punch), but I just can't handle that level of starchiness anymore. The problem is that cornstarch holds up well (that is, it won't break down or change form) in relatively low-moisture, low-heat applications—like, say, lemon meltaways. The eggless dough doesn't contain any liquids at all, and in the oven, its internal temperature remains well within a range that cornstarch can tolerate. That means it's still functionally a raw starch by the time you bite into a meltaway, allowing the crumbs to soak up moisture like a sponge and leaving a chalky residue on your tongue. Yum.
Having recently discovered the joy of powdered sugar made from tapioca starch, which breaks down at much lower temperatures, I immediately wondered if a simple swap could solve my meltaway dilemma.
And freshness is where it's at for these cookies, so, to put that feeling front and center, I decided to prepare the dough in a food processor, which can grind bits of finely zested lemon into even tinier pieces, coaxing out more essential oil for an even stronger flavor.
(As a lengthy aside: Because the dry mix is so powdery and fine, merely turning on the food processor will send up a fog of powdered sugar, flour, and starch that will creep from every crevice. To avoid coating my kitchen in a layer of dust, I loosely covered the bowl with a sheet of plastic wrap before closing the lid—something I do with most recipes simply to cut down on clean-up.)
After grinding until the zest disappeared, I tossed in cubes of cold butter and pulsed to form a stiff dough. Since meltaways contain more butter than every other ingredient combined, I knew the dough would benefit from a long chill. Given that I wanted to keep the meltaways thin, I opted to treat them like a traditional icebox cookie, rolled into a log and refrigerated until firm.
From there, it was a simple matter of slice 'n' bake, and I pulled the cookies from the oven as soon as I noticed their edges beginning to brown. While the cookies were still a little warm, I finished them off with a generous dusting of powdered sugar on both sides—bottom first, so the tops stayed pretty.
Even with a cornstarch-y dough, that first batch proved far more delicious than the meltaways I remembered, largely thanks to their small size.
With that solid-but-starchy foundation established, I rolled up my sleeves to begin adapting the recipe to tapioca. What I didn't anticipate was that my very first experiment would prove to be the best of them all. Made with tapioca starch, the shortbread baked up visually identical to the original, with the same buttery richness and lemony flavor. But, freed from that damnably starchy aftertaste, their delicate texture truly seemed to melt away on my tongue.
It's rare to nail anything on the first try, so I continued adjusting the levels of starch and powdered sugar through another dozen trials. But in the end, I found that any increase in sugar or decrease in starch caused the cookies to spread and brown. I even played around with other starches and found that arrowroot works just as well. Both are easy to find in stores or online, from brands like Bob's Red Mill. (You can also find paper sacks of tapioca starch in your favorite Asian market, often for a fraction of the price.)
I'll always be partial to tapioca starch. Not only did it redeem powdered sugar in my eyes, it was the first starch to help me reclaim a sweet and simple childhood treat that I thought I'd given up for good. Now, if only I could figure out how to re-create that rainbow sherbet punch...