70g flaxmeal (just ground up flaxseeds)
2 eggs
1 tbs olive oil
1/2 tsp baking powder
pinch salt OR 2 tsp cocoa and a little splenda

Mix everything together to a wet dough, pour into a well greased bread tin or a silicon bread mold. Bake in a 200C or gas 6 oven for 16-18 minutes, until a toothpick comes out clean. The texture is something like a muffin (you could also bake it in muffin moulds) and close enough to chocolate cake for the children to eat it as birthday cake. It keeps well in a closed container.