In a large mixing bowl, combine butter, shortening, and sugar. Beat until fluffy. Turn the mixer down and add egg, vanilla, and almond extract. Add baking powder. Add flour and cornstarch and mix thoroughly. If the dough seems crumbly, keep mixing with a paddle attachment. It’ll come together!
*Start with 3 ½ cups of flour, and if the dough seems too soft, add the last ½ cup of flour.