Preheat oven to 350 degrees.
Grease a 9x13 inch baking dish (or line with parchment paper for easy removal)
In a medium bowl, add the flour, cocoa, baking powder and salt and whisk together.
In a mixing bowl, blend cream butter, yogurt and sugar until creamy. (about 2 minutes).
Then beat in the eggs, vanilla, and food coloring and mix for an additional minute.
Add the flour mixture until dough forms, careful not to over mix.
Press the dough into the bottom of the 9x13 inch pan.
Bake for 15-20 minutes (or until toothpick inserted into the center comes out clean).
Allow to completely cool before frosting.
Cream Cheese Frosting
Beat the cream cheese and butter together.
Add the powdered sugar and vanilla.
Beat until smooth.
Frost the top of the bars
Cut into squares.