1. Add the Oreos to a freezer bag and crush with a rolling pin until you get fine crumbs. Melt the butter, let cool down a bit, then add to the bag with the crumbs. Mix until the Oreo crumbs are evenly moist. Line an 8 inches (20cm) springform tin with baking parchment and transfer the crumbs to the tin. Press to the bottom and sides to create a nice crust. The sides should almost go up to the rim of the springform tin. Place in the fridge until needed.

2. Preheat the oven to 320°F (160°C). Add the cream cheese, mascarpone, and sour cream for the filling to a large bowl and mix to combine. Add the sugar, vanilla extract, and orange zest and mix in. Add the eggs and mix until well combined. Sift the flour on top and mix in. Pour the mixture into the prepared tin and bake for 50-60 minutes. The edges should be set and the center still a bit wobbly if you move the tin. The cheesecake gets firmer when cooling down, so do not overbake it. Take out of the oven and cool down completely on a wire rack.

3. While the cake is cooling down, prepare the jelly layer. Add the gelatin leaves to a bowl with cold water and let soak for about 5 minutes. Add the sugar, liquor, and water to a small saucepan and mix to combine. Heat up until the sugar has dissolved – do not let it cook. Remove from the heat, squeeze the soaked gelatin leaves a bit to remove excess water, then add to the saucepan. Mix and let the gelatin dissolve completely. Gradually add the orange juice and mix in until all is well combined. Set aside and let thicken slightly for about 45-60 minutes. When the cheesecake has cooled down and the orange mix has thickened a bit, pour it on top of the cheesecake. Get rid of any air bubbles on the surface and place the cheesecake in the fridge for at least 4 hours or overnight. Remove the cheesecake from the fridge 30 minutes before serving and decorate with some orange slices (optional).