1 1/3 cups plus 1 tablespoon all-purpose flour
1/2 cup whole grain kamut flour
2/3 cup cornstarch
1/4 teaspoon baking powder
1/4 teaspoon salt, preferably fine sea salt
1/2 pound plus 2 tablespoons (2 sticks plus 2 tablespoons) unsalted butter, softened
1/2 cup granulated sugar
2 teaspoons vanilla extract
1 1/2 teaspoons rose extract gel (or substitute 8 drops rose flower essence)
3 tablespoons granulated sugar, for dusting over the surface of the just-baked block of shortbread
Preheat the oven to 325 degrees F. Film the inside of a 7 by 7 by 2-inch baking pan with nonstick oil spray. Lengthwise and widthwise, line inside of the pan with sheets of overnproof parchment paper, leaving about 3/4-inch of paper to extend on all four sides. Film the inside of the pan with nonstick oil spray. Set aside.
For the dough, sift the all-purpose flour, kamut flour, cornstarch, baking powder, and salt onto a sheet of waxed paper.
Place the butter in a medium-size mixing bowl. Using a hand-held electric mixer, cream the butter on high speed until very smooth and lightened, about 4 minutes. It is important to have the butter very soft and creamy at this point in order to create a tender baked cookie. Add 1/2 cup granulated sugar in 3 additions, beating for 45 seconds after each addition. Blend in the vanilla extract and rose flower gel or rose flower essence. On low speed, blend in the sifted mixture in 2 additions, mixing quickly but thoroughly after each portion is added. The resulting dough will be soft. Overworking the dough at this point would create a heavy cookie.
Scrape the dough into the prepared baking pan, pressing it in an even layer with your fingertips and smoothing it into the corners, using a narrow offset palette knife. Avoid compressing the dough.
Bake the sweet in the preheated oven for 50 minutes, or until set and evenly light golden on top. Avoid unbaking the shortbread.
Cool the sweet in the pan on a cooling rack for 3 minutes.
For the finish, after the 3-minute cooling, sprinkle the granulated sugar evenly over the top of the block of shortbread. Cool for 5 minutes. Using a small, sharp knife, cut the block of shortbread into quarters, then cut each quarter into 3 long bars/logs or 4 squares. Cool completely at room temperature (do not refrigerate), then gently recut the squares and remove them to an airtight cookie tin, using an offset metal spatula.
one dozen logs or 16 squares
on baking day, or up to one week in advance, stored in an airtight container
◊ the butter should be very soft (but not oily) to create the flakiest batch of cookies
◊ the butter must be well-creamed until smooth and pearly
◊ a small amount of baking powder improves the texture of the finished shortbread