Preheat oven to 350°F. Spray a 9×13-inch baking dish with nonstick cooking spray.
Whisk the flour, granulated sugar, cocoa powder, baking powder and salt in a large bowl to combine. Add 1 egg, 1/2 cup of the melted butter, buttermilk, and red food coloring. Mix to form a dough. Press into the bottom of prepared baking dish.
Beat cream cheese in a large bowl with an electric mixer until smooth. Beat in the remaining 2 eggs, vanilla, and remaining 1/2 cup melted butter. Add confectioners’ sugar and beat until the mixture is creamy. Pour over crust.
Bake for about 20 minutes, being careful not to overbake. The center should still be a bit gooey.
Cool completely. Dust with confectioners’ sugar, then cut into 16 bars. Store in the refrigerator.