Crush the biscuits to a fine crumb. Melt the margarine and stir into the crushed biscuits. Press into the bottom of the springform tin and place in the fridge for at least half an hour to firm up
Melt together the chocolate and oil and set aside as you want this melted but not hot
Whisk the cream cheese until smooth, then add the icing sugar and vanilla and whisk in. If you are using a very thick cream cheese alternative add 1 tbsp dairy-free milk or yoghurt to get a smoother consistency.
Pour in the cooled melted chocolate and stir until fully combined.
Pour the chocolate mixture over the chilled base and level off the top. Return to the fridge for at least an hour to set.
Remove from the fridge and mark the portion slices on the top of the cheesecake (this is so you can ensure each slice gets a fair share of chocolates on top)
Decorate each slice with a generous amount of chocolates.
Keep the cheesecake in the fridge until ready to serve. This will keep well for 2-3 days in the fridge.