Preheat the oven to 180°C (160°C fan forced). Grease a 22cm round springform cake pan and line the base with baking paper. Also, line a small baking tray with baking paper.
For the brownie base and topping, make the brownie mix as directed on the box using eggs and butter. Spread two-thirds of the brownie mix into the round pan. Spread the remaining brownie mix on the prepared tray to about 1cm thick. Bake both for 15 minutes or until firm to touch around the edges and the middle is just set. Cool on a wire rack. Remove the round brownie from the pan, peel off the paper and place the brownie back in the greased pan, top-down. Crumble the remaining browning into pieces and set aside.
Place 1/4 cup (60ml) cool water in a small, heatproof bowl and sprinkle the gelatine over the top. Whisk to combine and set aside for 5 minutes for the water to absorb into the gelatine. Heat the gelatine mixture in the microwave, in 10 second bursts on high heat, until the mixture is melted and clear.
Meanwhile, beat cream cheese, 1/2 cup (125ml) of the frosting, sugar and salt in a large bowl with electric mixer until smooth. Scrape down the sides of the bowl, add the gelatine mixture and beat until smooth. Fold in whipped cream.
Spread half of the cheesecake mixture over the prepared base. Dollop with half the remaining frosting and half of the crumbled brownie. Spread with the remaining cheesecake mixture and press the remaining brownie lightly on top. Refrigerate for 3-4 hours or until firm.
Decorate with raspberries and gold leaf.
Warm the remaining frosting following tub directions. Drizzle over the cheesecake.