Preheat the oven to 350°. Line a 9×9 baking pan with parchment paper.
In a small sauce pot, melt butter over medium-low heat and whisk in chocolate chips and brown sugar. Keep whisking for a few seconds and turn off the heat. Whisk until chocolate chips melt, and take off the stove. (Do NOT overheat or chocolate will seize.)
Transfer the chocolate mixture into the mixing bowl and let it cool for a few minutes so you don't scald the eggs.
Whisk in the eggs just until incorporated.
Whisk in Baileys Irish cream and vanilla extract until incorporated.
Sift in cocoa powder and add in the flour and salt. Whisk until the ingredients are incorporated.
Transfer into the prepared baking dish and spread the batter evenly.
Bake for 30 minutes. Take the pan out of the oven and let the brownies cool for about 30 minutes before cutting.
Notes
Bailey's Whipped Cream: Beat 1 cup coldheavy whipping cream, 1/4 cup cold Baileys and 1/4 cup powdered sugar with a whisk attachment on medium-high speed. Continue mixing as you slowly pour in the 1/2 tsp. vanilla extract. Once stiff peaks form, it’s ready! Make sure to add the the whipped cream only to cooled brownies!
Bailey's Cream Cheese Frosting: Let your cream cheese and Irish cream warm up for about 30 minutes before making the frosting. Beat together 8 oz of room temperature cream cheese, 1/2 cup white granulated sugar, 2 tbsp.sour cream and 1/4 cup of room temperature Baileys in a bowl for 2-3 minutes. Once it's nice and smooth, you can spread it over the cooled brownies.
Bailey's Ganache: Chop a 4 ozbaking chocolate bar and place it in a small mixing bowl. Bring 4 tbsp Bailey's to simmer in a small sauce pot. Don't let it boil. Pour the hot Bailey's over the chopped milk chocolate and stir with a whisk until melted and smooth. Note that this will make a nice thin layer of ganache. If you'd like the layer to be thicker, simply double the recipe. Spread over cooled brownies!