Line the base and sides of a 20 cm/8 in round springform cake tin with baking paper.
Place the biscuits in a food processor and blitz until very finely crushed. Alternatively, place them in a sealable freezer bag wrapped in a tea towel and bash them with a rolling pin.
Tip the crushed biscuits into a bowl and mix in the melted vegan butter. It should resemble damp sand.
Tip the biscuit mixture into the prepared tin and pack the crumbs down really firmly and evenly, use the base of a glass to help press them down.
Optionally for a crisper base, bake it in a preheated oven at 180°C/160°C fan/350°F/gas mark 4 for 10 minutes. Set aside to cool.
Place the cashews in a large bowl, cover with a generous amount of boiling water and leave to soak for 1 hour.
Drain the cashews really well and place in a blender along with the cream cheese, firm tofu, sugar, treacle, melted butter, lemon juice, vanilla extract, orange zest, ginger, cinnamon and nutmeg.
Blend the filling mixture until it is extremely smooth with no hint of graininess. This can take a while so stop regularly to let the blender cool down and scrape down the sides as needed.
Pour the cheesecake filling on top of the biscuit base and spread it level. Refrigerate for 8 hours until set. You can also place it in the freezer for about 4 hours.
To serve the cheesecake, remove the springform tin and carefully peel off the baking paper. If you like you can smooth round the edges with a palette knife to neaten. Keep refrigerated.