Preheat oven to 400 degrees F/ 200 degrees Line the bottom of a 7 inch/ 18 cm spring form pan with a circle of parchment paper. Wrap the pan tightly with two sheets of aluminium foul, to prevent the cheesecake from leaking.
Combine all ingredients and mix them until smooth. Press the crust to the bottom of the prepared pan. Leave the pan in the fridge, while preparing the filling.
Combine all ingredients, except the chocolate in a large mixing bowl and beat them until smooth.
Pour the filling into the pan, over the crust. Break the chocolate into small pieces and drop them inside the filling to sink in.
The filling will be very runny so put it immediately in the hot oven, to avoid leakage. Decrease the temperature to 360 degrees F/ 180 degrees Bake until the top is set and the edges become yellow (about 1 hour). Switch off the oven and open its door just a bit. Let the cheesecake cool inside for 30 minutes. Remove the cheesecake from the oven and let it cool until room temperature. Cover with aluminium foil and refrigerate for 6-8 hours or overnight.
Before serving cover with the topping and decorate with fresh berries and leaves.
In a small saucepan combine the berries and xylitol. Heat until the mixture starts simmering.
Remove the pan from the heat and add the chia seeds. Let cool for 15 minutes, before topping the cheesecake with it.