Ingredients

• 1 cup (2 sticks) unsalted butter, softened, cut into bits
• 1/3 cup confectioners' sugar
• 2 cups all-purpose flour
• 1/4 cup rice flour or cornstarch
• 1/4 teaspoon salt (optional)

Instructions

1. Preheat oven to 350 degrees F. Line two 8-inch round cake pans with aluminum foil, pressing foil evenly into pan to fit well. Grease foil. Or, use two shortbread molds and prepare according to manufacturer's directions.
2. In the large bowl of an electric mixer, beat butter and sugar until fluffy, about 2 to 3 minutes.
3. Whisk together all-purpose flour, rice flour or cornstarch, and salt. Add to the butter mixture in 2 batches, beating lightly with a wooden spoon. Dough will be rough, but pliable. With lightly floured hands, gather dough into a ball. Cut it into 2 equal pieces with a knife.
4. Again with lightly floured hands, press each half of the dough into the prepared pans or molds. Crimp edges or press down gently with the tines of a fork. Using the point of a small, sharp knife, score each pan of shortbread into 8 wedges (be careful not to cut more than halfway through the dough), much as if you were marking a pie to be cut later. (You do not need to score the shortbread if you are using shortbread molds.)
5. Bake for 18 to 20 minutes, or until shortbread is a uniform honey color, firm to the touch and not brown around the edges.
6. Cool shortbread completely in the pan. Score the shortbread again with a knife. Grasp foil on 2 sides and lift carefully to remove shortbread from pan. Break gently into wedges.
7. Note: If you like your shortbread a little crunchier, bake for an additional 5 minutes.