I realized recently I have been doing so much cake-work in my sweetcraft practice. Time to get back to basics. The most basic of all basics, shortbread, which is, if executed well, hardly basic.
Recipes for shortbread should be, well, pretty short--this is a recipe about butter, and if you start mucking things up with bips and babs (chocolate, lavender, caramel, etc) you're not really doing shortbread. Shortbread's purpose begins and ends with chauffeuring butter to your palate.
I wanted to create a shortbread recipe that would ensure the most toasty, buttery flavor possible while maintaining an exceptionally tender texture, not overly sandy, dull, or pasty. (Almost) as always, a little bit of extra work makes a dessert that is enormously more extraordinary. We've got three different sugars, two different butters, two different flours, a resting period, and a bit of egg yolk coming down the line--still, it's a very easy recipe.
Let's start with butter, as we should. It makes sense to want to reach for a really expensive, European high-fat/cultured butter for a recipe like this. And, indeed, we will. But as most bakers will tell you, you can't always swap in your Plugra for your standard American butter. It has a slightly higher fat content, less water, and is often cultured (making it slightly acidic), all of which affects recipes substantially. Rest assured this recipe is adjusted for Euro-butter factors.
We're also going to to use browned butter for half of the total butter requirements. All-browned butter in a shortbread recipe would create a butter a little too solid, since so much more water is evaporated from browning the butter, little is left to create steam/rise in the dough. But we really, really want those little flavor bits that browned butter imparts, so a balance must be struck.
With our higher-fat Euro butter in play, we need to make some adjustments to the flour. Cake flour has the ability to absorb more liquids than all-purpose flour, but using all cake flour can leave you with a chalky shortbread. All purpose with a small portion of cake flour gives us the right texture and prevents the shortbread from becoming greasy due to the extra fat. Definitely use your scale here; in one test batch I added just half an ounce more flour and the resulting shortbread was too dry.
Often a little bit of starch is also added to the dough in order to help soak up some of that fat, and give the shortbread a silky tenderness. This is where our mix of sugars comes in. White sugar melts fast and will create the right structure for the starches and proteins, powdered sugar adds a silkiness thanks to the cornstarch, and brown sugar just for that light molasses-y flavor.
All that's left, ingredient wise, is some egg yolk. Purists would balk at adding egg to shortbread, but purists would also be too busy choking on a mouthful of their powdery sand cakes that explode into dust upon biting into them to admit that the old fashioned recipe for shortbread needs a little more structure, a little more protein in order to make it flaky and tender instead of a dust bomb. Just half an egg yolk; a full yolk would prevent shortbread from being "short" enough (refers to the extremely fine/melting crumb). Trust me, you'll see.
I also knew that, as with many other cookie recipes, letting the dough rest would result in a more flavorful shortbread. Unrested, you are baking flour particles next to butter particles in your dough, which is fine. But rested, you are baking butter-soaked flour particles, which is great. I tested the recipe at three stages--unrested, rested for two hours, and rested overnight. Guess which one tasted best.
The unrested dough tasted mostly like flour. Both rested doughs tasted fantastically buttery and complex. Texture-wise, they weren't that different; the unrested dough was slightly chalkier.
The good news is that the batch rested for two hours tasted pretty great, almost as great as the 24-hr shortbread, so if you are in a hurry you'll still come out ahead with just a little resting.
Thick shortbread is better than thin shortbread if you want a truly tender bite instead of just a crisp one. Double baking the shortbread a la biscotti will give you the most beautifully browned and crisp exterior; I highly recommend it. I also recommend removing the center of your shortbread if using a round tart pan since the center will never really get cooked, and those pointed edges of each wedge will always break anyway (see my set up above; I use a metal biscuit cutter as a center stay). A rectangular pan also works great here, just make sure you are using a pan with a removable bottom as the shortbread is really delicate.
The Best Shortbread Ever
makes 12-14 wedges
8 Tbsp (4 oz) salted cultured European-style butter, soft but cool (Plugra, Lurpak, etc)
8 Tbsp (4 oz) browned butter, cooled to semi-solid
1/4 c. (1.75 oz) packed light brown sugar
2 Tbsp (0.9 oz) sugar
2 Tbsp (0.5 oz) powdered sugar
1/2 large egg yolk
2 tsp vanilla extract or scraped vanilla bean
1/4 tsp salt
2 c. (9.5 oz) all-purpose flour
1/4 c. (1 oz) cake flour (I use White Lily)
1 Tbsp Demerara or sanding sugar for sprinkling
With a hand mixer, beat softened butters, sugars, salt, 1/2 egg yolk, and vanilla extract/beans until just combined and smooth, about 2 minutes (stop before mixture begins to fluff up). Add flours and beat just until dough comes together; do not over mix.
Press dough into a 8" tart pan or cheesecake pan with removable bottom and pat the top with wet fingers to smooth. Dock the dough with a fork and sprinkle demerara sugar on top. Cover and allow to rest in the fridge for at least 2 hours, preferably overnight.
Bake in an oven preheated to 275 degrees for 45 minutes. Remove from the oven and turn the heat up to 375. Allow shortbread to cool in the pan for 20 minutes, then cut into wedges and transfer carefully to a baking sheet lined with parchment paper and bake for an additional 15 minutes until toasted to a golden brown. Allow to cool completely before storing in an air-tight container.