Preheat oven to 325°F. Grease an 8-inch round baking pan and line with parchment paper (a spring form pan works best). Set aside.

Melt chocolate and butter in a double boiler. Remove from heat and transfer to a large bowl. Alternatively melt chocolate with butter in a small bowl in the microwave at 30 second intervals; stirring in between. In a small cup, mix espresso powder, water, vanilla and salt; stir into chocolate. Set mixture aside to cool.

With an electric mixer on medium-high speed, beat eggs, ½ cup xylitol, stevia and cocoa powder until it falls in thick ribbons when the beater is lifted, about 6 minutes. In three additions, fold eggs into the chocolate mixture.

Pour batter into prepared pan and smooth top. Bake 30-35 minutes, or until a toothpick inserted near middle of cake comes out with a few moist crumbs and cake is evenly raised. Cool completely on a wire rack. To remove cake, run a knife around edge of pan. Dip bottom of pan into hot water for 1 minute, then turn cake out onto cutting board. (if using a spring form pan, carefully remove sides and serve on the platter.) Turn right side up onto a serving platter. Serve with coconut cream and raspberries, if desired.