Finely grind the gingersnaps in a food processor. Add cinnamon and butter and process until moistened. Press mixture into a greased 9-inch tart pan with removable bottom.
In a saucepan over medium heat, melt chocolate with heavy cream until smooth. Remove from heat. In a medium bowl mix together egg yolks, egg, sugar, flour, pepper, salt and cinnamon. Slowly add chocolate mixture to the bowl, stirring until smooth and combined. Pour filling into prepared crust.
Bake tart on a sheet pan in an oven at 325°F for 30 minutes. The filling should be slightly puffy at the edges and the center completely set. Cool on a wire rack for 20 minutes. Then remove tart from sides and cool completely.
Serve with whipped cream and a dusting of cinnamon.