Chocolate mousse and crunchy ginger slice

Grease a 27 x 17cm slice pan with cooking oil spray and line base and sides with baking paper, allowing sides to extend 3cm above tin.

Put 250g butternut snap biscuits in the bowl of a food processor and pulse until fine crumbs.

Add 50g melted butter and 1 tsp ground ginger, then pulse until combined. Press mixture into prepared tin and refrigerate.

Meanwhile, put 400g chopped dark chocolate in a large heatproof bowl over a saucepan of simmering water. Stir until smooth, then set aside to cool for 5 minutes.

Put 2 x 300ml tubs thickened cream in a large bowl and beat using an electric mixer until soft peaks form.

Using a whisk, fold cream into chocolate in 3 batches.

Pour over biscuit base and smooth top. Refrigerate for 3 hours.

Dust with cocoa, top with chocolate shavings and serve.