Bring bourbon to a boil in a small saucepan, remove from heat and add chocolate chips, stirring until smooth.
Combine the flour, cocoa, baking powder and salt and mix well with a whisk.
Combine sugar and butter in a large bowl, beat at medium speed until well combined, then add vanilla and eggs; beat well and add flour mixture and bourbon mixture to sugar mixture, beating at low speed just until combined.
Spread batter into a 9-inch square baking pan coated with cooking spray.
Bake at 350° for 25 minutes or until a wooden pick inserted in center comes out clean.