Grease and line the base and side of a 22cm springform pan. Place biscuits and cinnamon in a food processor and process until you have fine crumbs. Add butter and process until combined.
Using the back of a metal spoon, press the biscuit mixture evenly over the base and up the side of the pan. Refrigerate for at least an hour.
Meanwhile, sprinkle gelatin over a ¼ cup of cold water in a small bowl. Stir with a fork until the gelatin has dissolved and become sponge-like. Set aside. (When you need to use the gelatin place the bowl over hot water to melt it so it turns liquid before adding it to your mixture.)
Place the cream cheese, sugar and mixed spice in a clean food processor and process until smooth. Gradually add half the cream and process until combined. Add rum and brandy and mix until combined. Add the gelatin mixture and process.
Pour the batter into the pan with the chilled biscuit base. Refrigerate overnight or until set. Using an electric mixer, beat the remaining cream until just-firm peaks form.
Transfer cheesecake to a plate.
Dollop with cream and sprinkle with extra cinnamon to serve.
