Preheat the oven to 180c/155f (fan). Line two 20cm/8 inch springform cake tins with baking parchment. Set aside.
In a measuring jug, whisk together the soy milk, lemon juice and vegetable oil. Set aside.
In a medium bowl, sieve together the plain white flour, cocoa powder, baking powder, baking soda and instant espresso. whisk to combine and set aside.
Place the vegan butter and caster sugar in the bowl of a stand mixer fitted with the creaming paddle attachment. Beat on medium speed until combined into a smooth paste.
In a small bowl, whisk together the water and psyllium husk powder then immediately add to the stand mixer and beat on medium speed until combined - don't worry if the mixture looks split at this stage.
Add half of the flour mixture to the stand mixer and beat on low speed until just combined. Add half of the soy milk mixture and beat again. Repeat until all the flour mixture and soy milk mixture is added.
Divide the batter between the two cake tins. Shake and tap the tins gently to create an even layer of batter. Place in the oven to bake for 30 minutes.
When baked, remove from the oven and set on a wire cooling rack for 10 minutes. Carefully remove the cake tin and leave on the rack again to cool completely. Meanwhile make the chocolate cream cheese frosting.