To make the base use a food processor to whizz up the digestive biscuits into crumbs, or gently crush them with a rolling pin in a bowl
Mix in the melted butter into the biscuit crumbs and press the mixture into the bottom of a 23cm springform tin. Put it in the fridge for 30 minutes to chill
For the cheesecake filling use a food mixer with a whisk attachment or an electric hand whisk to mix together the cream cheese, icing sugar and cocoa powder until smooth with no lumps
Add the double cream and whisk until it is very thick and holds it's shape
Smooth the mixture into the tin on top of the biscuit base, then put it in the fridge overnight, or for at least 4 hours, to set
Remove from the tin and put on your serving plate. Smooth the sides with a butter knife to create a neater finish
To make the dark chocolate ganache, put the ingredients into a bowl and microwave for 20 seconds, then stir. Continue microwaving in 10 second blasts, stirring between each blast, until melted and smooth
Spread the dark chocolate ganache over the top of the cheesecake
To make the white chocolate ganache, put the ingredients into a bowl and microwave for 20 seconds, then stir. Continue microwaving in 10 second blasts, stirring between each blast, until melted and smooth. If you are using the whitening powder, sieve it into the melted mix and stir in
Put the white chocolate ganache into a piping bag and pipe a swirl, starting from the centre of the cheesecake and working your way out
Using a cocktail stick, starting from the centre of the cheesecake and working your way to the edge, drag the cocktail stick through the ganache to create the spiderweb pattern
Serve immediately, store any leftovers in the fridge and eat within 3 days
Video
Notes
It is really important to stick to the ingredients and use full fat cream cheese and double cream (a cream with a 48% fat content), both of these ingredients are essential to ensure the no bake cheesecake sets. If you want to make a low fat version, I suggest doing this in small dessert glasses or ramekins as they will not set well enough to be sliced.
I am based in the UK and I find that Philadelphia cream cheese is the thickest and best quality cream cheese to use for no bake cheesecakes. I have made many cheesecakes with supermarket own brand cream cheeses too, and they have worked great. If you can though, I think it is worth spending a little more for Philadelphia (and no they haven't paid me to say this!)
For an extra black and spooky biscuit base, use black cocoa powder. If not, regular cocoa powder works great too.
You can use either butter or baking spread for the biscuit base, I find that baking spread makes the cheesecake easier to remove from the tin as it doesn't make the base set as solidly.
You can find lots of answers to common no bake cheesecake questions on my How To Make A No Bake Cheesecake guide. If you've never made a no bake cheesecake before, I highly recommend reading through my guide first!
Although I provide cup measurements, I highly recommend weighing your ingredients out using digital kitchen scales. It is the most accurate way to measure ingredients and will ensure the best results. Digital scales are very low cost and can be purchased for around £12 ($16.50).
For teaspoon (tsp) and tablespoon (tbsp) measurements, please use measuring spoons and not the type of spoons you eat with. Again this will ensure accuracy and provide the best results.