Entirely Elizabeth

0 Preheat oven to [wprm-temperature value="350" unit="F"]. Line a 9x13 baking pan with parchment paper and lightly grease with non-stick cooking spray.
3 In a bowl whisk together the all-purpose flour, cornstarch, baking powder, and salt. Set aside. 
1 Using a hand mixer or stand mixer fitted with the paddle attachment, beat together the softened unsalted butter and granulated sugar for 2 to 3 minutes. It should be pale in color and fluffy in texture.
2 Add the egg, vanilla extract, and almond extract. Beat together until combined, about 1 minute. 
4 Add the dry ingredients and beat together until the dry mixture is absorbed. This takes around 30 seconds to 1 minute.
5 Pour the sugar cookie dough into baking pan and lightly press (using your butter wrappers or waxed paper) until it evenly covers the pan.ELIZABETH'S NOTE: If the cookie dough gets sticky, place it in the refrigerator for 5 to 10 minutes and try again.
6 Bake for 14 to 16 minutes or until the edges are very light brown and the center no longer glistens. Remove from the oven and allow them to cool completely.
7 Make the frosting. Beat together the softened unsalted butter, vanilla extract, almond extract, and salt until fluffy, about 2 minutes. 
9 Add the powdered sugar in 3 increments, allowing it to fully absorb between each addition. Slowly add the corn syrup and continue to beat until it is fully incorporated, about 2 minutes. 
8 Remove half of the frosting and fold in 1 drop of green food coloring, set aside.
10 Cut the cooled 9x13 sugar cookie bar in half. Frost the first piece with green frosting and decorate with sprinkles. Frost the second piece with white frosting and decorate with sprinkles.
11 Cut the green bar into Christmas trees and the white bar in squares (see recipe notes for diagrams). Serve!