- In a small saucepan, bring the water and flaxseed to a boil. Simmer over low heat for 30 minutes. Drain the mixture, keeping only the viscous liquid coming from the seeds. Let cool.
- With the rack in the middle position, preheat the oven to 180 °C (350 °F). Line the bottom of a 20-cm (8-inch) springform pan with parchment paper.
- In a bowl, combine the flour, baking powder, and salt. Set aside.
- In another bowl, whisk together the sugar, cocoa powder, oil and vinegar with an electric mixer for about 3 minutes. Add the egg substitute and beat until well blended. Add the dry ingredients alternately with the soy beverage and vanilla.
- Pour the batter into the pan. Bake for 55 minutes or until a toothpick inserted in the centre of the cake comes out clean.
- Let cool before unmoulding and let completely cool on a wire rack.
- Place the chocolate in a bowl. Set aside.
- In a small saucepan, bring the soy beverage and corn syrup to a boil.
- Pour over the chocolate and let melt for 1 minute. Whisk until the ganache is smooth. Refrigerate for about 1 hour or until the ganache has thickened and is spreadable. If needed, soften quickly in the microwave oven.
- Cut the cake in half horizontally. Fill and frost the cake with the ganache.
Freeze the remaining egg substitute in an ice cube tray. 1 cube averages 1 egg.