Make the Brownie Base:

1. Preheat oven to 350°F (175°C). Grease and line an 8×8-inch baking pan with parchment paper.
2. In a large bowl, mix melted butter and sugar until combined.
3. Beat in eggs and vanilla until smooth.
4. Sift in cocoa powder, flour, salt, and baking powder. Stir until just combined.
5. Spread batter evenly into the prepared pan.
6. Bake for 20–25 minutes or until a toothpick comes out with moist crumbs. Do not overbake.
7. Cool completely in the pan before adding mousse.

Make the Chocolate Mousse:

1. In a microwave-safe bowl, combine chopped chocolate and milk. Microwave in 20-second bursts, stirring each time, until smooth. Let cool to room temperature.
2. In a separate bowl, whip the cold heavy cream and powdered sugar to soft peaks.
3. Gently fold the cooled chocolate into the whipped cream until fully incorporated.
4. Spread mousse over the cooled brownie layer. Chill in the fridge for 1 hour.

Make the Ganache Topping:

1. Heat the heavy cream in a small saucepan until it just begins to simmer.
2. Pour over the chopped chocolate. Let sit 2 minutes, then stir until smooth.
3. Cool slightly, then pour over the chilled mousse layer.
4. Refrigerate for another 1–2 hours until fully set.

To Serve:

• Lift brownies out of the pan using parchment.
• Slice with a sharp knife dipped in hot water for clean cuts.