Vanilla shortbread is a cookie-jar classic, with an ingredient list so simple it's hard to improve upon—the straightforward combination of butter, sugar, and flour doesn't leave much wiggle room, except for an obligatory dose of vanilla and salt.
That doesn't mean our hands are tied, though. Not when there's butter to brown and sugar to toast! When we amp up the inherent flavor of these foundational ingredients, the shortbread gets a major boost in complexity without totally deviating from what we expect from this simple treat. Plus, these cookies feature a cameo from one of my favorite secret ingredients: malted milk powder.
Along with the brown butter and toasted sugar, it makes a shortbread cookie that's as tender and meltingly rich as a French sablé, but extra toasty and caramelized.
The process starts with making the brown butter, a familiar process for many home cooks, and one I put to good use in a lot of recipes: brownies, carrot cake, ricotta cookies, and my overnight waffles, to name a few.
If you haven't browned butter before, don't worry—it's super easy. Just melt the butter over low heat in a skillet, then increase the heat to medium and cook to boil off the water, stirring and scraping all the while. The butter will hiss and pop along the way as the water cooks off, then dairy solids in the butter will begin to brown. When the mixture quiets down and turns golden, you're done!
If you happen to have a leftover vanilla bean kickin' around the pantry after another project, toss it in while you're melting the butter to infuse the butter with a deeper flavor. (Don't abuse a fresh vanilla bean here; this is just a good way to get more mileage out of an oldie!)
As the butter cooks, adjust the heat as needed so that it doesn't cook too hard or fast. The idea is to cook off the water, then brown the milk solids; if the heat is too high, the solids may brown (or even burn) before the water has been driven off. Since the water isn't meant to be part of the recipe, it can derail the texture of the cookies, so pay close attention to the butter as it cooks, and keep an eye on the heat.
Whether or not you're using a vanilla bean, scrape the browned butter into the bowl of a stand mixer and set it aside until it's cooled to room temperature. If you're not in a hurry, this can be done several hours (or even days) in advance, but for those in need of cookies now, setting the bowl into a cold water bath will do the trick. The goal is to cool the butter only until it's thick and opaque, around 75°F (24°C), so I don't like to use ice, which can make the butter too cold and hard for the creaming method.
Because this recipe requires a solid chunk of downtime to melt, brown, and cool the butter, I almost always multitask with a concurrent batch of quick-toasted sugar. Compared with plain white sugar, this lightly caramelized sugar will reduce the sweetness of the dough, which in turn makes it seem richer, while adding a bit of caramel complexity.
If you happen to have it on hand, fully toasted sugar works well, too, as does the lightly toasted sugar left over from blind-baking a pie. It's a sliding scale of caramel flavor, so use what you have or toast what you need.
When the butter is creamy, soft, and opaque, I add the toasted sugar, along with salt, baking soda, baking powder, and a bit of malted milk powder. I've written in greater depth about it before, but malted milk powder is basically the umami bomb of dessert, and one of my favorite "tricks" for amplifying the natural flavor of recipes that rely on the rich complexity of ingredients like brown butter. (It works well with nuts, chocolate, and brown sugar profiles, too.)
Look for malted milk powder at any supermarket, where it's sold from brands like Carnation next to the hot cocoa mix, or buy it in bulk online. (My fave brand is Hoosier Hill Farm.)
After incorporating everything on low speed, I add vanilla extract to moisten the dough, then increase the speed to medium to cream the brown butter and sugar. When the mixture looks fluffy and light, I drop the speed back down to low before adding the all-purpose flour.
Once the flour disappears, I scrape the bowl and beater with a flexible spatula and fold the cookie dough a few times to be sure it's completely homogeneous. Next, I form it into a log using a large sheet of parchment.
Start by simply transferring the dough to the parchment and forming it into a roughly cylindrical shape by hand. From there, its shape can be tidied by wrapping it in the parchment and using a bench scraper to pull the paper tight. The final step is to tie off the ends with a bit of kitchen twine.
And hey—if a bit of dough gets pinched off in the process, just consider it a cook's treat.
This dough will need to be refrigerated at least four hours to make it firm enough to slice, but its flavor will improve with age, so I usually let it go at least overnight, if not over a whole weekend. That may be slightly annoying for those who need cookies right this second, but in the grand scheme of holiday dessert, a long refrigeration period gives this dough a major advantage in the "make-ahead" category.
However long it chills, let the dough stand at room temperature for about 10 minutes before slicing it into rounds with a chef's knife. Straight from the fridge, the brown butter gives the dough a slightly brittle quality that makes it prone to cracking and crumbling as it's sliced, so don't rush it. Once softened, the dough can be sliced without any fuss.
I bake the shortbread on a parchment-lined half-sheet pan until lightly browned, about 15 minutes at 350°F (180°C). They'll be hopelessly delicate and crumbly while warm, so cool the shortbread to room temperature directly on the baking sheet before stealing a bite.
Once cool, the shortbread will have a crisp bite that gives way to a shower of sandy crumbs that all but melt in your mouth, releasing the flavor of brown butter and caramelized sugar. It's a seductive combination that's perfect on its own, crumbled over ice cream, or simply served alongside a mug of tea.
In an airtight container, the shortbread cookies will keep for well over a month, making them an excellent candidate for the cookie jar or a welcome part of your holiday cookie spread.