• In the bowl of beat together butter, shortening, sugar and lemon zest with an electric stand mixer, medium speed until fluffy.
• Add in egg and mix until blended.
• Then add egg white, lemon extract and vanilla extract and mix until combined. Add the cake flour, cornstarch, baking powder and salt. Blend in just until combined.
• Place dough in an airtight container and refrigerate 2 hours.
• Preheat oven to 375 degrees during the last 10 minutes of refrigeration.
• Scoop out an even 1/4 cup of dough at a time and roll into a ball.
• Place dough ball on a lightly floured surface, sprinkle top lightly with flour.
• Light press to dough down with your hand, flattening it slightly.
• Then using something flat and smooth (such as the storage container lid), press and evenly flatten dough to 1/2" thick and 2 2/3" - 2 3/4 " in diameter.
• Place six cookies on a cookie sheet. Bake in 375 degree oven 9 - 11 minutes, just until edges begin to get golden.
• Allow to cool 5 minutes on baking sheet before transferring to a wire rack to cool. Cool completely then frost with Lemon Frosting.

For the lemon frosting:

• Combine butter, powdered sugar, lemon extract, and lemon juice in a large mixing bowl, using an electric mixer, whip until frosting is smooth and fluffy.
• Mix in food coloring if desired. Frost cookies with frosting and sprinkle cookies with yellow sprinkles if desired. Makes 12 cookies.