Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.

In a medium bowl, whisk together flour, baking powder, and salt. Set aside.

In a large bowl, cream together softened butter and granulated sugar until light and fluffy.

Beat in eggs one at a time, then stir in vanilla extract.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Spread the dough evenly into the prepared baking pan.

Bake for 20-22 minutes, or until the edges are lightly golden brown and a toothpick inserted into the center comes out clean.

Let the bars cool completely in the pan on a wire rack.

In a large bowl, beat together softened cream cheese and softened butter until smooth and creamy.

Gradually beat in powdered sugar until well combined and smooth.

Stir in milk and vanilla extract until the frosting reaches your desired consistency.

Once the cookie bars are completely cooled, spread the cream cheese frosting evenly over the top.

Immediately sprinkle with red, blue, and white sprinkles to create a patriotic design.

Cut into bars and serve.