Sift together coconut flour, cocoa powder, and baking powder over a bowl. Stir until well-mixed. Set aside.
In a large microwave-safe bowl, add baking chocolate and butter. Microwave until just melted in 30-second intervals, stirring in between.
Add sweetener, warm coffee, and vanilla to the chocolate mixture, whisking them in until dissolved.
Add eggs, vigorously whisking for a few minutes until smooth. Add coconut flour mixture, gradually whisking in until incorporated. Small lumps are ok.
Pour the batter into the prepared pan, spreading it out to the sides and smoothing the top. Let it rest for about 10 minutes while you preheat the oven to 300 F.
Bake at 300 F for 55 minutes or until an inserted toothpick in the center comes out clean with a few crumbs.
Let the cake cool in the pan for 30 minutes. While waiting, prepare the ganache in the next step.
In a bowl, add all ganache ingredients. Microwave until the chocolate is just melted in 30-second intervals, stirring in between. The texture should be very smooth. Refrigerate for 15 minutes or until the mixture has a spreadable consistency.
Slide a butter knife all around between the cake and the pan, and release the springform pan. Spread a thin layer of ganache on the top and down the sides of the cake. Cut into slices and serve.
This recipe yields 3 g net carbs per serving (1/12th slice of 9-inch frosted cake).