Shortbread
1 3/4 cup all purpose flour
2/3 cup superfine sugar*
2 sticks (1 cup) COLD butter, cut into 1/2 inch slices
1/4 cup rice flour OR cornstarch (I just learned from another SMF thread that cornstarch is called cornflour outside the US)
1/4 teaspoon salt
Put an oven rack in the middle position and heat the oven to 425 degrees F (220 C).
Reserve 1 Tablespoon sugar for a garnish. Mix the rest of the sugar, the flours, and salt in a mixer bowl. With mixer on low, gradually drop the butter cubes into flour. Mix about 4 minutes until the dough is like pale yellow, damp crumbs.
Speaking from experience, the dough should remain crumbly for a delicate sandy texture. If it comes together and forms a ball, the cookies will be less sandy and tender. If that is what you prefer, then you can knead the dough briefly so it makes a ball before going onto the next step.
Pour half of the crumbs (or half of the ball of dough) onto a cookie sheet. The sheet should be ungreased or you can cover it with parchment paper. Pat firmly into a disk 8 inches across and about 3/8 inch thick. Repeat with the other half. If you have room, you can put the second disk next to the first on the same cookie sheet. If not, use a second sheet. (Or you can use a clay shortbread pan like I do:
http://shortbreadpan.com/shortbread-pans/shortbread-pan-gallery/ )
Put shortbread in the oven and immediately reduce the temperature to 300 degrees. Bake about 50 minutes. Remove from oven and gently loosen the shortbread with a spatula if you aren't using parchment paper, but leave the shortbread on the sheet. Cut each disk into 16 wedges while the shortbread is still hot. Sprinkle with the reserved sugar.
Return to the turned-off oven, close the oven door, and let the shortbread cool in the oven. After completely cool, store in an airtight container. These cookies freeze beautifully.
*Superfine sugar: Blend regular sugar in a food processor for 30 seconds. The result is something between regular sugar and powdered confectioner's sugar.
Chocolate shortbread variation: Substitute 1/4 cup Dutch process cocoa for the rice flour