Make the cake first. Heat the oven to 180° C (360° F) and thoroughly grease a loaf pan.
Combine the flaxseed with 6 tbsp of water and let jelly. Rub off the peel of 1 1/2 lemons and juice them. Add water to the lemon juice to make it to 180 ml (3/4 cup). In a bowl combine all dry ingredients including the lemon zest and then mix all ingredients for the cake with a wooden spoon until the flour is incorporated. Don't overmix to prevent your cake from getting chewy.
Pour the batter into the loaf pan and bake in the oven for about 40 minutes, until a toothpick comes out clean. Let the cake cool in the pan for 10 minutes, then remove and let cool completely on a cooling rack.
Whip the cream. Combine the soy curd with the juice of 1/2 lemon and agave nectar with a whisk. Then fold in the whipped cream.
Crumble the lemon cake and pour some (about thumb-thick high) in individual jars or a baking dish and cover with cream. Then add another layer of crumbled cake and cover with cream on top. Decorate with lemon slices and lemon balm and keep refrigerated for 1 hour before serving.