4 x 154g packets chocolate cream-filled sandwich cookies, plus extra to serve
200g dark chocolate, broken into small pieces
STEP 1Oil a 20cm loose-bottomed or springform cake tin and line with baking parchment, ensuring the inside of the tin is fully covered. Whisk the cream, mascarpone, vanilla and icing sugar together in a large bowl until smooth and holding soft peaks.
STEP 2Line the base of the tin with a single layer of the cookies, (don’t worry if there are small gaps, as these will be filled with the cream mixture). Spoon over a third of the cream mixture and smooth with a spatula, spreading it to the edge. Repeat twice with the rest of the cookies and the cream mixture. Cover and chill for at least 24 hrs, or up to two days.
STEP 3Melt the chocolate in 20-second bursts in the microwave, or in a heatproof bowl set over a pan of simmering water, ensuring the base of the bowl doesn’t touch the water. Leave to cool for 10 mins. Unwrap the cake, remove it from the tin and peel off the parchment. Drizzle over the melted chocolate, letting it drip down the sides, and crumble over the extra cookies. Serve, or chill for up to 1 hr.