2- In a blender, add apple, milk, sugar, vanilla, oil, cocoa powder, and nutella. Blend until smooth keep aside.
3- In a separate bowl sift or whisk all the dry ingredients. Pour the wet ingredients on the dry and gently stir using a whisk or a spatula. Do not over mix.
4- Pour the boiling water in the batter and stir to combine. Pour the batter in 8×8 greased and floured baking pan, or you can use parchment paper, which I feel is best for this cake.
5- Bake for 30 minutes, then insert a toothpick in the middle, if it comes out clean, your cake is ready.
6- This cake should stay in the baking pan to cool, then refrigerate for at least an hour before serving. - This cake needs the one hour in the fridge for the flavors to come together. Cut into 12 squares.