Preheat your oven to 375 degrees.

In a medium sized bowl, combine your flour, baking powder and salt. Set aside.

In a large mixing bowl, cream together your butter and sugar for about 3 minutes until light and fluffy.

Add in your egg, sour cream and vanilla and mix till combined.

Slowly add in your flour mixture while stirring until everything is combined. (The dough will be crumbly)

Press the batter into a greased 9x13 baking dish and spread it out evenly with your hands or a rubber spatula.

Bake for 15-17 minutes or until edges just barely start to turn golden.

Allow to cool completely.

Mix together all your ingredients for your frosting until creamy.

Add in desired amount of food coloring.

Spread frosting evenly over cooled cookie bars.

Cut into squares and serve.