1. Whisk tofu with an electric hand beater or manually with a whisk, until completely smooth. Add remaining wet ingredients and the coffee powder if using. Whisk well.
2. Melt chocolate carefully in the microwave (on low checking every 30 sec or so) or over boiling water on the stove. Once chocolate is smooth, take it off the heat and let it sit for 5 minutes to cool, stirring occasionally. Add to the tofu mix and whisk on high (or put your elbow into it) as you want it nice and light.
3. For the crumb crust, crush roasted hazelnuts with a mortar and pestle, crumble in the biscuits (alternatively you could use a food processor), add the melted margarine and agave nectar and mix. Press into the bottom of your serving bowl(s), pour chocolate mousse on top, and refridgerate for a couple of hours or overnight.
4. If you're serving with fresh berries, wash and top with them right before serving.