Place 2 tablespoons of the coffee in a blender. Sprinkle the gelatin over the coffee and let sit for 2 minutes.
Bring the remaining coffee to a boil and pour over the mixture in the blender. Blend for 1 minute, until the gelatin is completely dissolved. Set aside for 5 minutes to cool slightly.
Add the liqueur to the blender mixture and blend to mix. Add the ricotta, sugar substitute, and cinnamon and blend until smooth. Pour the mixture into a large bowl and refrigerate for about 30 minutes, or until the consistency of pudding. Whisk until smooth and then fold in the whipped topping.
Spread the ricotta mixture into the piecrust, swirling the top.
Sprinkle the chocolate over the top.
Cover and chill for at least 3 hours, or until set.