Bases: Blend chia seeds to a flour, then add oats and blend again to a flour. Add all other ingredients except walnuts and blend until sticky, then add walnuts and pulse on low until roughly chopped but still with some texture.
Line a muffin tray with biodegradable wrap (wet the tray slightly to help it stick), then place 3-4tbsp of mixture in each casing. Press carefully to create 10 pie bases.
Chocolate Layer: Melt cacao butter, then whisk in remaining ingredients, and pour ½-1tsp of chocolate sauce inside each pie base, spreading out flat – place in fridge to set.
Caramel: blend all ingredients in a high speed blender until super smooth and creamy, scraping down the sides if needed. Pour a few tablespoons into each pie case, using a spoon to swirl the caramel into place. Place in freezer to set.
Bananas & cream: Take the top cream layer off two cans of coconut cream, and whisk in a bowl with a fork until thick and fluffy. Slice bananas thinly on an angle, and place banana slices concentrically on each pie, then top with a dollop of cream on each.
Topping: Slice a bar of dark chocolate into flakes, and sprinkle a few on the top of the cream. Place in the fridge for at least an hour preferably 2-3 for all the layers to set together.