Spray or line an 8x8 baking pan with parchment paper.  To make the brownies:  Combine melted butter and cocoa powder in a medium sized bowl. With a standing mixer or by hand, mix until incorporated. Add sugar and mix well. Add eggs, vanilla, and Irish cream, mixing until smooth. Add flour, and mix until fully combined. Pour into prepared pan and bake at 350° for 25-30 minutes. Remove from oven and allow to cool for ten minutes. 

To make the frosting:  Combine all ingredients and beat for about 30 seconds, or until smooth and lump free. Spread on to cooled brownies. 

To make the espresso drizzle:  Melt espresso chips in a microwave safe bowl on high for 1 minute. Whisk until smooth. Spoon onto frosted brownies, and using a knife, gently swirl into the frosting. 

Can allow to cool or cut and serve while topping is still warm. Serves 10-15.  Store in an airtight container at room temperature for up to three days. Enjoy!