Preheat oven to 375 degrees Fahrenheit. Lay parchment inside a 9x13-inch baking dish with the ends hanging out the 13-inch sides (so you can lift out the cookie after it's baked) and spray the 9-inch edges with pan spray since they aren't covered with parchment.

In a large bowl, cream together the butter and sugar. Add egg, milk and vanilla. Mix well.

In a separate bowl, combine the flour, baking powder and salt. Add dry ingredients to wet ingredients until combined.

Split dough in half and color one half orange and one half yellow.

Press the yellow cookie dough onto the bottom of the baking dish; I used a mini rolling pin to roll mine evenly across the bottom of the pan.

Press orange cookie dough onto the yellow cookie dough layer. I found it easiest to roll the orange cookie dough onto a lightly floured counter about the size of the dish, cut the orange dough into large squares and then assemble the squares on top of the yellow layer, smoothing over the cracks.

Bake for 17 to 20 minutes or until edges are lightly golden. Cool completely.

Pulling on both sides of the parchment paper, lift the cookie dough out of pan. Trim the crisp edges with a knife, if desired.

Prepare The BEST Cream Cheese Frosting and spread it evenly over cooled cookie bars. Cut the large slab of cookie in half lengthwise, and then cut into triangles. Enjoy!