Step 1: Preheat your oven to 350°F (175°C). Grease your baking pan or line it with parchment paper for easy removal.
Step 2: In a medium saucepan over low heat, melt the unsalted butter and 1 cup of semi-sweet chocolate chips together. Stir frequently until smooth. Remove from heat and let cool slightly.
Step 3: In a separate bowl, whisk together the flour, cocoa powder, salt, and baking powder.
Step 4: Stir in the granulated sugar, Irish cream, vanilla extract, and egg into the cooled chocolate mixture. Mix until well combined.
Step 5: Gradually add the dry ingredients to the wet mixture, stirring gently until just combined.
Step 6: Fold in the remaining 1 cup of semi-sweet chocolate chips into the batter.
Step 7: Pour the batter into your prepared baking pan and bake for 25-30 minutes, or until a toothpick comes out with a few moist crumbs.
Step 8: While the brownies are baking, whip the whipping cream in a bowl until soft peaks form. Gradually add the 1/4 cup of Irish cream and continue to whip until stiff peaks form.
Step 9: Once the brownies are cool, spread the whipped Irish cream on top and drizzle with extra Irish cream if desired.