Pour the chickpea brine into a very clean bowl. Beat with an electric hand beater or stand mixer on high until stiff peaks form, gradually adding the icing sugar. This could take 5-10 minutes. To check if it is ready, carefully invert the bowl of the aquafaba egg whites. If the aquafaba doesn’t slide down then it is ready.

Custard
Into a medium saucepan, add the soy milk and cornflour and whisk to combine, ensuring the cornflour has dissolved. Add the sugar, butter, vanilla and turmeric and whisk well. Heat over a medium heat, stirring occasionally. 

Once the custard thickens, reduce heat to low and continue to stir for a further 1-2 minutes. Take off the heat and pour into a large bowl. Hand beat the custard for a couple of minutes to cool a little.
Scoop the cream cheese into the custard and beat together with an electric hand mixer until smooth. Fold in the aquafaba a little at a time until it is well combined.

Combine the coffee and liqueur in a medium bowl. Dip the biscuits in one at a time for 5 seconds, to allow the coffee to soak in. Line a casserole or trifle dish with a layer of the dipped biscuits.

Scoop approximately half of the prepared custard cream over the biscuits, creating a thick layer. Repeat with another layer of dipped biscuits and a layer of custard cream. Garnish with a generous dusting of cocoa power and/or grated dark chocolate. Cover and refrigerate for a minimum of 2 hours to overnight. The tiramisu is best served the next day.