Preheat your oven to 350°F (175°C) and line a 9x13 inch baking pan with parchment paper, ensuring a slight overhang on the sides for easy removal.
In a large mixing bowl, cream together 1 cup of softened butter and 1 1/2 cups of granulated sugar for 3 to 5 minutes until the mixture is pale and fluffy.
Add the eggs, egg yolk, and 1 tablespoon of non-alcoholic vanilla flavoring to the butter mixture, beating until well combined and smooth.
In a separate medium bowl, whisk together the all-purpose flour, baking powder, and salt to ensure even distribution of leavening agents.
Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined; avoid overmixing to maintain a tender crumb.
Press the dough evenly into the prepared 9x13 inch pan using lightly floured hands or a piece of parchment paper to prevent the dough from sticking.
Bake for 18 to 22 minutes. The bars are done when the edges are just barely golden and the center is set but still looks slightly soft.
Remove the pan from the oven and place it on a wire rack to cool completely, which typically takes 1 to 2 hours. The bars must be cold before frosting.
To prepare the frosting, beat 1/2 cup of softened butter in a clean bowl until smooth. Add the powdered sugar, heavy cream, and the remaining non-alcoholic vanilla flavoring.
Whip the frosting on high speed until light and airy. If using natural coloring, fold in the strawberry powder until the desired pink hue is achieved.
Spread the frosting in an even layer over the cooled bars using an offset spatula, then cut into 24 uniform squares before serving.