Preheat your oven to 350°F (175°C). Line a 9x9 inch baking pan with parchment paper, leaving some overhang on the sides for easy removal later.
In a large mixing bowl, beat together the very soft unsalted butter and confectioners sugar until light and fluffy. This should take about 2-3 minutes. Gradually add in the all-purpose flour, corn starch, and salt until just combined.
Using your hands or a spatula, press the shortbread mixture evenly into the bottom of the prepared pan. Make sure it’s packed down well to create a solid base.
Bake the shortbread base in the preheated oven for about 15-18 minutes or until it is lightly golden around the edges. Once done, remove it from the oven and let it cool slightly.
In another bowl, beat together the softened cream cheese and granulated sugar until smooth. Add in the egg, 2 tablespoons of flour, and almond extract, mixing until just combined.
Pour the cream cheese mixture over the cooled shortbread base. Use a spatula to spread it evenly across the surface.
Return the pan to the oven and bake for an additional 25-30 minutes, or until the filling is set and lightly golden on top.
Once baked, remove the pan from the oven and let it cool completely in the pan. While it cools, prepare the frosting by beating together the softened butter, confectioners sugar, almond extract, and cream or milk until it reaches your desired consistency.
Spread the frosting over the cooled cream cheese layer, and sprinkle the slivered almonds on top for a beautiful finish.
Once frosted, use the parchment overhang to lift the bars out of the pan. Slice into squares or rectangles and serve! Enjoy the delightful balance of almond and cream cheese flavors in every bite.
