Preheat your oven to 350 degrees and spray a 8x8 baking pan with some nonstick cooking spray.
In the bowl of a stand mixer, cream together the butter, granulated sugar, and brown sugar together.
Add in the egg and vanilla and almond extracts. Mix well to combine.
In a large bowl, sift together the flour, baking powder, cornstarch, salt.
Add flour mixture to wet mixture on low speed. Beat until just combined.
Spread cookie batter into prepared pan and bake for 20-25 minutes.
Let cookie base cool completely before adding frosting.