1. Preheat the oven to 350°F and line a jelly roll pan with parchment paper. Lightly grease the parchment so the brownie layer releases easily.

2. Melt the butter and semi-sweet chocolate together until smooth, then let the mixture cool for a few minutes.

3. Whisk in the granulated sugar, brown sugar, eggs, and vanilla extract until the batter looks glossy and well combined.

4. Sift in the flour, cocoa powder, salt, and baking powder, then stir gently until no dry streaks remain.

5. Spread the batter evenly in the prepared pan and bake for 12 to 15 minutes, just until the top is set and the brownie layer is soft.

6. Turn the warm brownie sheet onto a clean towel dusted lightly with cocoa powder or powdered sugar, peel away the parchment, and carefully roll it up from the short end. Let it cool completely.

7. Beat the cream cheese and powdered sugar until smooth. In a separate bowl whip the heavy cream, then fold it into the cream cheese mixture to make a fluffy filling.

8. Gently unroll the cooled brownie sheet, spread the filling evenly over the surface, and roll it back up into a log.

9. Transfer the log to a serving platter and spread the outside with chocolate ganache or chocolate frosting.

10. Create a bark-like texture with a fork, then finish with powdered sugar and chocolate shavings if desired.

11. Chill for at least 1 hour before slicing and serving.