For the base, pulse oats in a food processor until roughly ground. Add dates, cacao, coconut oil and maple syrup. Process until you have a sticky consistency.
Line a rectangular baking dish with baking parchment. Spoon the oat mixture inside and press down tightly with your hands.
For the chestnut cream place all ingredients in a food processor and blend until you have a smooth, creamy consistency. Spread evenly on top of the oat base. Refrigerate for 10 minutes.
In the meantime prepare the chocolate glaze. Warm up the coconut oil until melted. Stir in cacao and maple syrup. Let cool. Pour evenly on top of the chestnut cream and refrigerate for 2-3 hours. Cut in slices and serve or freeze for later consumption.