Preheat oven to 350 degrees. Line a 13x9 inch pan with parchment paper or aluminum foil and grease. Set aside.

In a medium bowl, add the flour, cocoa powder, salt, baking power, and baking soda, and stir to combine.

In a large mixing bowl, beat together the butter and sugar until soft and fluffy, around 5 minutes. Add the eggs, one at time, mixing until fully incorporated. Slowly stir in the vanilla and food coloring. Add the dry ingredients in batches, mixing until just combined.

Scoop the batter into the 13x9 inch pan and press down with a spatula to spread evenly into the pan. Bake for 15-20 minutes, or until a toothpick inserted into the center comes out clean. Cool completely.

While the cookie bars cool, add the butter and cream cheese to a large mixing bowl and beat until combined and fluffy, around 5 minutes. Add the powdered sugar in batches and beat gently until combined. Add the vanilla, then beat for an additional 3 minutes. Frost the cookie bars, cut, and enjoy.