Preheat the oven to 175 degrees Celcius.
Lina a baking pan with parchment paper.
Add apple sauce and egg to a blender and mix until smooth.
Add the sugar and mix again.
Combine the rest of the ingredients in a bowl.
Add the dry ingredients to the blender and mix until smooth. Dont mix too long.
Pour the batter to the prepared baking pan and bake in the oven for 25-28 minutes. Until a toothpick comes out clean.
Meanwhile combine the ingredients for the frosting in a bowl and mix using a electric mixer until smooth. Store in the fridge until using.
Let the cake cool completely before adding the frosting on top.