- Preheat oven to 325 degrees. Line an 8-inch pan with enough parchment paper that the length drapes over the sides.
- Melt the butter for 30 seconds in a large microwavable bowl and whisk until butter is smooth. Stir in sugar, cocoa powder and salt. (It will still be grainy; that’s OK as it will smooth out when you add the rest of the ingredients.)
- Add the vanilla and eggs one at a time to the cocoa mixture, stirring vigorously after each addition. You want the batter to look thick and shiny. Gently stir in the flour until it is mostly combined and then stir vigorously again. Pour into the prepared pan and bake for 30 minutes or until a toothpick inserted in the center still has a bit of moist batter. Cool completely on a rack. Lift parchment edges out of pan when ready frost.
- Place cream cheese and butter in bowl of a stand mixer and beat until smooth and light. About 5 minutes.
- Add the Irish Cream Liqueur and mix until combined.
- Add the powdered sugar one cup at a time, mixing well after each addition.
- Frost when brownies are completely cool. Refrigerate until serving.