Preheat your oven to 350°F (175°C), and line an 8×8-inch baking pan with parchment paper.

Cream together the softened butter, granulated sugar, and brown sugar until smooth and fluffy.

Add the egg, almond extract, and vanilla extract to the mixture. Mix until well combined.

Whisk together the flour, baking powder, cornstarch, and salt in a separate bowl. Slowly mix this dry blend into the wet ingredients.

Spread the batter evenly into the prepared pan and bake for approximately 15 minutes or until the edges are lightly golden.

For the frosting: In a mixing bowl, whip together the softened butter and powdered sugar, then gradually add heavy cream and vanilla extract until fluffy.

Frost the cooled cookie layer with the prepared frosting and sprinkle with festive Christmas sprinkles.