The classic proportions for shortbread are 1, 2, 3: one part sugar, two parts butter and three parts flour. These days shortbread recipes are both sweeter and richer than that. Surprised? The below recipe, inspired by Cook’s Illustrated, boosts the sugar content by about 50% and the butter by about 25%, which is OK by me. The formula is:
8.75 ounces (1 3/4 cups) all-purpose flour
1.25 ounces (1/4 cup) of either corn starch or rice flour
5 ounces (about 2/3 cup) extra fine sugar
1/4 teaspoon salt
8 ounces (2 sticks) unsalted butter, cold and cut into small cubes
Preheat your oven to 425. Combine the flour(s), sugar and salt in the bowl of a mixer fitted with a paddle attachment. Stir on low to blend. Turn the mixer up to medium speed and add the cold butter. Beat 2-3 minutes until the butter is fully incorporated and a dough comes together. It will range in texture from crumbly to smooth depending on your flour and the ambient temperature.
Shape into classic “petticoat tails” by lining a 9″ cake layer pan with a round of parchment or waxed paper, laying in the dough, covering it with another round of waxed paper, and pressing down on it with a second layer pan. Refrigerated the dough 30 minutes to firm it. Loosen the edges of the dough with a short knife, peel off the top layer of waxed paper, and turn the round out onto a parchment-lined sheet pan. Peel off the second piece of waxed paper.
Put the round into the oven and immediately turn the heat down to 300. Bake 20 minutes, then remove the round from the oven. Insert a 2″ round cutter in the very center of the round (this will be removed later). Score the shortbread with a sharp knife, like spokes on a wheel, into 16 pieces. Use a cake tester or wooden skewer to poke regular holes in the shortbread (the holes are part decorative, part functional, as they allow gas and steam to escape, keeping the shortbread dense).
Return the shortbread to the oven and bake an additional 40 minutes until only very lightly browned. Remove from the oven and sprinkle on additional sugar. Cool 10 minutes then remove the round cutter (saving the cookie at the center for yourself) and slice the shortbread along the scores into blunt pie-shaped pieces. Cool completely, a minimum of 3 hours.