Preheat oven to 190°C. Toast hazelnuts on a baking sheet until skins begin to crinkle, about 7 minutes. Leave oven on. Rub hazelnuts with kitchen towel to remove as much of the skin as possible. When hazelnuts are cool enough to handle, coarsely chop and set aside.
In small bowl, stir together biscuit crumbs, oil and 1 tablespoon water. Press mixture into bottom and part way up sides of 20-cm springform pan. Bake for 8 minutes or until crust is set. Cool on rack. Reduce oven to 180°C.
In small bowl, combine cocoa and 1⁄4 cup water until well moistened. In food processor, combine tofu, cheese, chocolate, white sugar, brown sugar, flour, whole egg, egg whites, vanilla and cocoa mixture, and process until very smooth.
Pour batter into baked crust. Bake for 40 minutes. Reduce oven to 120°C, sprinkle nuts on top and bake for 10 minutes or until just set. Cool to room temperature; refrigerate for 2 hours or until chilled.
The egg in this cheesecake offers vitamin D and the canola oil provides omega-3 fatty acids.