First, prepare your tin. Line a 20cm (8-inch) square baking tin with parchment paper, leaving some overhang on the sides to make it easier to lift the cheesecake out later.

To make the base, place the 300g of Oreo biscuits into a food processor and blitz until they form fine crumbs. If you don't have a food processor, pop them in a sturdy plastic bag and bash them with a rolling pin.

Transfer the biscuit crumbs to a medium bowl and pour over the 100g of melted unsalted butter. Mix thoroughly with a fork until all the crumbs are evenly moistened and resemble wet sand.

Tip the mixture into your prepared tin and press it down firmly and evenly using the back of a spoon or the base of a glass. I find that giving the base a quick 10-minute chill in the freezer while I make the filling really helps it set up perfectly.

In a large bowl, using a stand mixer or an electric hand mixer, beat the 500g of room temperature cream cheese and 150g of sifted icing sugar together on a medium speed until completely smooth and free of lumps. This should take about 2-3 minutes.

Add the 1 tsp of peppermint extract and a few drops of green food colouring, if using. Mix again until the colour is evenly distributed. Start with a tiny amount of colouring; you can always add more.

In a separate, clean bowl, whip the 300ml of cold double cream until it holds stiff peaks. Be careful not to over-whip it. You can find excellent guidance on how to whip cream correctly if you're unsure.

Gently fold the whipped cream into the cream cheese mixture in two stages using a spatula. This keeps the filling light. Once combined, fold in the 100g of roughly chopped Oreos.

Spoon the cheesecake filling over the chilled biscuit base and spread it out into an even layer with your spatula.

Cover the tin with cling film and place it in the fridge to set for at least 4 hours, though overnight is even better for a really firm set.

Once set, use the parchment paper overhang to lift the cheesecake from the tin. Drizzle with melted dark chocolate and sprinkle over extra crushed Oreos before slicing into 12 bars to serve.