Preheat oven to 375. Line a 9" round baking pan with unbleached parchment round and spray with olive oil on the sides.
Use a double boiler to slowly melt the chocolate, stirring constantly. Let it sit to cool while you prepare the rest of the batter. Alternately, use the microwave and stir in between each 15 second interval of cooking.
In a medium sized mixing bowl mix applesauce almond butter and maple syrup together until fully combined, thick and creamy.
Sprinkle on almond flour, cacao powder and salt and mix until dry ingredients are fully incorporated into the wet.
Peel apple and grate over the bowl with cake batter. Mix well. Then add in the melted chocolate and mix to thoroughly combine.
Pour batter into prepared pan and bake in preheated oven for 35 minutes, until toothpick inserted into the center comes out clean.
Cool cake COMPLETELY before moving ahead. Cake can be wrapped as is and refrigerated until ready to frost/serve. You can leave cake in pan and cover with plastic wrap OR, remove from pan once completely cooled and wrapped and then refrigerate or freeze.
Frosting
Place almond butter, maple syrup, cacao powder, vanilla extract and salt into the bowl of a small food processor or mini blender. Process until smooth and creamy. Add water and process again.
Frosting can be made ahead and stored in the refrigerator in an airtight container for up to 2 weeks. Frosting may thicken when in the fridge, so gently stir in 1 tablespoon of warm water to bring it to a spreadable consistency.
Spoon frosting onto top of cake and use an offset spatula to evenly spread.
Notes
This recipe makes ONE cake, with enough frosting for that single layer cake. Check out my 5-minute vegan chocolate frosting recipe for more details and measurements to frost a double layer cake.