The Book: Baking With Julia
I hesitate to write this for two reasons. The first, because I am embarrassed to admit that, until Sunday, I had never made Chef Gale Gand’s genius recipe for Hungarian Shortbreads. In my defense, while I bake shortbread cookies often and in various guises, I never would’ve thought to look for something so simple in this beautiful tome, based on Julia Child’s PBS series with guest chefs. Intricate pastries, sure. Show-stopping cakes, absolutely. But bar cookies? They awaited me on Page 327.
The second reason: I really hate to give up the secret to an amazing, airy shortbread that, from here on, will be my go-to recipe.
The dough ingredients aren’t surprising: butter, flour, sugar, eggs, baking powder, salt. I’d wager you could use your usual dough. The key is technique. (Though this version hits my sweet spot with its pound of butter and corresponding measures of flour and sugar.) The central layer is a homemade rhubarb jam—a pound of rhubarb (frozen, in this case) simmered with half a cup each of sugar and water, and half a vanilla bean—divine and ridiculously easy to prepare.
The trick is this: Divide the dough (which has been mixed just long enough to incorporate all ingredients), wrap it in plastic, freeze for 30 minutes and then . . . grate it into a 9 x 13-inch pan. Yup. Break out the box grater, use the side with the widest holes and shred the dough evenly across the dish, leaving the pieces loose. Patting it down is going to get you the usual shortbread (yummy but hardly feathery, which is where this will go if you don’t play with your food). Move pieces only to close large gaps. Spoon the cooled, homemade jam over the first layer, then grate the second ball of dough evenly over the top.
While grating the dough may seem onerous, it’s not. And it is so worth it. After 40 short minutes in the oven, you’ll end up with a pan full of ethereal, buttery, crumbly squares—tart fruit streaking through the center—that taste like you expended way more effort or, possibly, have been hiding your pastry chef training. My advice: Don’t share your secret.
Three Points Kitchen 
That is fascinating. I wonder how she came up with that idea. Probably an antidote to leaving the dough in to chill too long and only realizing it when she had just enough time to bake?
But possibly more fascinating, that you had rhubarb in the freezer ready to go.
That — or it gets all melty when you press it into the pan (and sticky)? I never saw it as a problem, but sticky dough on hands was mentioned in the recipe as if it were an issue. And when frozen rhubarb goes on sale, I buy it! The season is too short and I love tart fruit!