1. Line an 8×8-inch baking pan with parchment paper, leaving an overhang on two sides for easy lifting. Lightly grease the parchment and sides of the pan. Preheat the oven to 350°F (175°C).

2. In a heat-safe bowl, combine the melted butter and semi-sweet chocolate chips. Warm gently (in the microwave in short bursts or over a double boiler), stirring until smooth and glossy. Let cool slightly until warm but not hot.

3. Whisk in the granulated sugar and brown sugar until the mixture looks thick and shiny. Add the eggs one at a time, whisking well after each addition.

4. Stir in the Baileys Irish Cream and vanilla extract until fully combined and the batter is smooth.

5. Sift the all-purpose flour, cocoa powder, and fine sea salt over the wet ingredients. Gently fold with a spatula just until no dry streaks remain, being careful not to overmix so the brownies stay fudgy.

6. In a separate bowl, beat the softened cream cheese until smooth. Add the powdered sugar, Baileys Irish Cream, vanilla extract, and cornstarch. Mix until creamy and slightly thick but still easily spoonable.

7. Pour the brownie batter into the prepared pan and spread it into an even layer. Spoon the cream cheese mixture over the top in several dollops.

8. Use a butter knife or skewer to gently swirl the cream mixture through the brownie batter, creating marbled patterns without overmixing the two layers together.

9. Bake for 28–34 minutes, or until the edges are set and a toothpick inserted near the center comes out with a few moist crumbs but no wet batter. The cream swirl should look just set and slightly puffed.

10. Place the pan on a wire rack and cool completely. For the cleanest slices and best texture, chill the brownies in the refrigerator for at least 1–2 hours. Lift out using the parchment, cut into 16 squares, and serve slightly chilled or at room temperature.