Preheat oven to 350 degrees F (175 C) and grease a 9-inch cake pan with baking spray or a dab of coconut oil.

Place the chopped chocolate in a small saucepan over very low heat. Melt the chocolate, stirring occasionally, and remove from the heat the second it is melted. 

Meanwhile, put the ground flaxseed in a large mixing bowl and add the water. Whisk to combine and set aside for a few minutes until the flax mixture thickens up.

Add the applesauce, mashed banana, brown sugar, and vanilla extract to the flax mixture and whisk to combine.

Add the melted chocolate to the mixture of wet ingredients and whisk to combine. 

Add in the cocoa powder, almond flour, espresso powder and salt. Using a spatula, gently fold the dry ingredients into the wet. The mixture will be thick and slightly glossy. 

Pour the chocolate cake batter into a lined cake pan and bake for 50-60 minutes, until the top is set and the edges start to pull away from the pan. 

Remove from the oven and leave to cool completely before slicing and serving. 

Garnish with fresh raspberries.