Preheat your oven to 175°C. Line a 5-inch square baking pan with parchment paper, ensuring the bottom and sides are fully covered for easy removal later.

Place 120 g dark chocolate and 70 g unsalted butter in a heatproof bowl. Set the bowl over a pot of gently simmering water. Stir until the chocolate and butter are completely melted and the mixture is smooth and glossy. Remove from heat and let cool until just warm to the touch.

In a large bowl, combine 3 room-temperature eggs and 50 g granulated sugar. Whisk with a hand whisk until the sugar dissolves and the mixture becomes pale and uniform.

Pour the cooled chocolate-butter mixture into the egg mixture and whisk until fully combined and smooth.

In a separate small bowl, whisk together 70 g cake flour, 10 g cocoa powder, and 3 g baking powder. Sift the dry ingredients directly into the chocolate-egg mixture. Use a spatula to fold gently until no dry flour remains and the batter is smooth. Be careful not to overmix.

Pour the batter into the prepared pan and use a spatula to spread it evenly. Bake at 175°C for 25 minutes. The brownie is ready when the surface is slightly cracked and it springs back when lightly pressed. Remove from the oven and let the brownie cool completely to room temperature.

Place 80 g room-temperature cream cheese in a mixing bowl. Add 10 g granulated sugar and use a silicone spatula to stir until the mixture is smooth, creamy, and completely free of lumps.

Add 70 g room-temperature heavy cream to the cream cheese mixture. Use a hand whisk to whip until it reaches a thick, yogurt-like consistency.

Soak 5 g gelatin sheets in a bowl of cold water for 5–10 minutes until softened. Remove the gelatin sheets from the cold water and squeeze out any excess liquid. Add the softened gelatin to 40 g warm milk and stir until completely dissolved.

Slowly pour the warm milk-gelatin mixture into the cream cheese mixture. Fold gently with a spatula until the cheesecake mixture is smooth and uniform.

Pour the cheesecake mixture over the completely cooled brownie layer. Use a spatula to spread it evenly to the edges. Place the pan in the freezer for 30 minutes to allow the cheesecake layer to set quickly.

Place 60 g dark chocolate in a bowl. In a small saucepan, heat 70 g heavy cream until it reaches about 70°C—you'll see small bubbles forming around the edges, but do not bring it to a boil. Pour the hot cream over the dark chocolate and stir gently until the mixture is smooth and glossy.

Let the chocolate glaze cool until just warm to the touch.

Remove the pan from the freezer. Slowly pour the cooled chocolate glaze over the set cheesecake layer. Gently tap the pan on the counter to help the glaze spread evenly across the surface.

Place the cake in the refrigerator and chill for at least 4 hours, allowing the glaze and cheesecake layer to fully set and meld together.

Once fully chilled, remove the cake from the pan by lifting the parchment paper. Peel away the paper and slice into bars or squares. Serve immediately.