When I was a kid, I thought of E.L. Fudge (ELF) cookies as the antithesis of Oreos, with crispy vanilla wafers surrounding a dark-chocolate filling. They were also perfectly wonderful even if you didn't have ready access to a glass of milk, which made them one of my favorite cookies to buy at a gas station during our family road trips.
You'd think just about any vanilla cookie with a chocolate filling would get the job done, but ELFs are crunchy in a way homemade cookies rarely are, almost like a cracker. So, to make something similar at home, I knew I couldn't reach for that old pastry standby, the 1-2-3 dough: one part sugar, two parts butter, and three parts flour by weight. It produces a cutout cookie that holds its shape nicely in the oven, but one far too tender for an ELF.
So my recipe scales back on the butter to give the cookies a little more bite. While fat is a tenderizing ingredient, cutting down doesn't make the cookies tough so much as it makes them a bit more resilient—crunchy, if you will. It also makes for a drier dough, necessitating a splash of milk to eliminate any crumbliness.
In cookies, the lactose in milk can improve both flavor and browning via the Maillard reaction, but milk also contributes enough water to facilitate gluten development. If it's not incorporated thoughtfully, that can be a Very Bad Thing, as excess gluten formation goes hand in hand with toughness and shrinking. But, when approached with care, it can also create a cracker-like snap...just what I wanted in a crispy sandwich cookie.
Because of that unusual addition, I bring the dough together like a cake/cookie hybrid, first creaming the butter and sugar together until fluffy and light (more info on the importance of that step here), then alternating additions of milk/vanilla and flour until both have been thoroughly incorporated.
The result is a soft and pliable dough that can easily be rolled out to a thickness of one-eighth of an inch—a super-important detail, because the cookies will ultimately be paired with a chocolate filling. If the cookies are rolled too thick, you can easily wind up with a monstrously thick sandwich cookie. Now, you may be thinking that bigger is better (MOAR COOKIES!), but in a crunchy cookie like this, less is more unless you want to chip a tooth. So, please, grab a ruler!
As with almost any dough, there's no shame in using a big handful of flour to prevent it from sticking to your work surface or pin; it's far easier to dust away the excess with a pastry brush than to unstick a dough plastered to the counter. Don't hold back! Once the dough is nice and thin, you can give it a pass with a docking tool to add a little polka-dotted flair (I like this one from Fox Run).
Unfortunately, there are no tiny-Keebler-Elf-shaped cookie cutters to be had in this cruel world, but I discovered an owl-shaped cutter with approximately the same dimensions as Ernie Keebler himself—just over an inch wide and a wee bit over three inches long. (You can see a side-by-side comparison here.)
Of course, you can use any cookie cutter, but remember that the yield and the amount of filling required will vary according to the surface area of each cookie, so avoid upgrading to a significantly larger size. Whatever cutter you choose, arrange the cutouts on a parchment-lined half sheet pan, and bake until they're golden around the very edges but still rather pale in the middle. If needed, rotate the baking sheet 90° about halfway through to ensure even browning.
They may be called E.L. Fudge cookies, but the filling is really just a simple chocolate frosting that can be whipped up in the time it takes for the fresh-baked cookies to cool. Just sift some Dutch-process cocoa with powdered sugar, and slowly beat it into a bowlful of butter. The mixture may seem dry at first, but keep at it until the frosting comes together in a dark and fudgy paste. To that end, reach for an ultra-dark Dutch-processed cocoa, like Cacao Barry Extra Brute; its alkalinity gives the chocolate an earthy depth that seems fudgier than the brighter, fruitier notes of natural cocoa.
If you're the sort of person who generally stays away from powdered sugar–based frostings, try using a tapioca-based powdered sugar instead. Compared to traditional cornstarch-based powdered sugar, these alternatives dissolve more readily on the tongue. Since almost every tapioca-based brand happens to be organic as well, you can also expect a bit more complexity of flavor due to the natural molasses content in raw cane sugar. For the full scoop and a more in-depth comparison, check out my write-up here.
Once the filling is creamy and smooth, transfer it to a disposable pastry bag and snip off the end to create a roughly quarter-inch opening. If you happen to have one, feel free to use a plain coupler or a quarter-inch pastry tip for a more polished look.
If your cookies are symmetrical, flip half over before piping in the filling; if their shape is irregular, you'll want to leave them right side up to ensure the edges of the sandwich cookies line up. In either case, pipe a generous stripe of filling across the designated "bottoms," then gently press them together with the remaining halves.
From there, any sane person would immediately devour a cookie or two, which is to be expected and enjoyed. Just beware: The soft, freshly piped filling has a tendency to come squishing out the sides.
To solidify the filling a bit, transfer the cookies to an airtight container and refrigerate about 15 minutes. Afterward, it'll retain a much firmer consistency at room temperature; perhaps not as firm as the filling in a commercially manufactured cookie, but as far as I'm concerned, the creamier texture is a major win. Just don't tell Ernie, okay?
PS: For those with a taste for history as well as cookies, my forthcoming book includes the curious story of Godfrey Keebler, a German immigrant who founded a bakery in Philadelphia just after the Civil War; it's his name and legacy that accompany every package of Keebler cookies today.