Pre-heat the oven to 180º.
Grease a 20 cm (8 inches) round baking pan with melted vegan margarine and dust itlightly with flour.
In a large bowl, combine all the ingredients for the dry mixture. Set aside.
In a bowl of a food processor, combine the agave nectar with the muscavado sugar. Process, at medium speed, until creamy. Add the apple juice, soy milk and the banana and process for additional 2 minutes, or until totatlly smooth.
Slowly pour the wet mixture into the bowl with the dry ingredients, mixing everything with a spatula. Even though you shouldn’t overmix the batter, make sure it doesn’t have any lumps.
Transfer the cake batter to the prepared pan.
In the meantime, peel and core the apples and cut them into thin slices. Then, arrange the apple slices evenly on top of the cake. Sprinkle it with the remaining tablespoon of muscavado sugar and a pinch of ground cinnamon. To finish things off, evenly distribute the margarine pieces on top of the cake.
Bake the cake in the preheat oven for 30 to 35minutes, or until the top is golden brown. Let it cool for 10 to 15 minutes in the pan, after which you should transfer it to a wire rack or large plate to cool down completely. To do this, carefully flip the cake onto a large plate(it will be upside down), and then use another plate to flip it again. Serve warm or at room temperature.