Ingredients

• 2 (19.8 ounce) packages fudge brownie mix (such as Duncan Hines®)
• 1 cup Irish cream liqueur (such as Baileys®)
• 2/3 cup vegetable oil
• 2 eggs
• 1 cup unsalted butter, softened
• 5 tablespoons Irish cream liqueur (such as Baileys®)
• 4 cups confectioners' sugar

Instructions

1. Preheat oven to 350 degrees F (175 degrees C).
2. Butter the bottom of a 10 1/2x15 1/2-inch jelly roll pan.
3. Place fudge brownie mix into a large bowl; beat in 1 cup of Irish cream liqueur, vegetable oil, and eggs until the mixture forms a smooth batter.
4. Spread the batter into the prepared jelly roll pan.
5. Bake in the preheated oven until the brownies are set and a toothpick inserted into the center comes out clean, about 20 minutes. Remove pan from oven and allow to cool completely.
6. Beat unsalted butter in a large bowl until smooth; beat in 5 tablespoons Irish cream liqueur until mixture is creamy.
7. Slowly beat in confectioners' sugar, 1 cup at a time, until frosting is desired stiffness; spread frosting on brownies to serve.