Preheat the oven to 300 F and generously butter eight of your 6-oz ramekins or you can use 3 of 4 oz mini cake pans with the melted butter. Dust the bottom and sides of each ramekin with some of the cocoa powder, tapping out the excess. Set the prepared ramekins on a baking sheet and set aside
To prepare the chocolate, put 1/2 cup of heavy cream in a small saucepan and bring just to a boil over medium heat. Set aside
Combine the chocolate, sugar, and five-spice powder in a large, heat-proof bowl. Set the bowl over a pot of gently simmering water and cook, stirring until the chocolate is completely melted, about 5 minutes. Add the heated cream to the melted chocolate and mix well. Remove the bowl from the heat and set aside to cool
Combine mascarpone cheese and the remaining of the 1/2 cup heavy cream in a large mixing bowl and beat with electric mixer until smooth. Add the eggs, one at a time, beating well after each addition. Add the chocolate mixture and mix on medium speed until just combined. Do not overmix
Divide the batter among the 8 ramekins until each is 3/4 full. Bake until the centers are just set, about 1 hour. Remove the cakes from the oven and set aside for 10 minutes before unmolding
Meanwhile, prepare the whipped cream by beating the heavy cream and sugar together in a large bowl with an electric mixer on high speed until soft peaks form
Unmold each cake by running a knife around the edge of the cake and inverting it onto a dessert plate. If you want to serve them warm , garnish each cake with a dollop of whipped cream