For the cupcakes, preheat the oven to 325F and line a muffin tray with 12 paper liners.
Cream together the butter and Swerve Confectioners in a large bowl, and then beat in the eggs, water, heavy whipping cream, vanilla, dissolved espresso powder, and stevia glycerite.
Whisk together the almond flour, cocoa powder, coconut flour, baking soda, baking powder, and salt in a medium bowl.
Stir the dry ingredients into the wet and let the batter rest for 2 minutes.
Divide the batter into the lined muffin wells. Bake until a wooden pick inserted in the center of a cupcake comes out clean or with just a couple crumbs, about 25 minutes. Cool completely before frosting.
For the frosting, mix the butter and crème fraiche into the melted, still warm cacao butter. Stir in the salt and vanilla bean paste, and then the Swerve Confectioners. Cool to room temperature, and then place a piece of plastic wrap directly on top of the frosting and chill 30 minutes in the fridge (the frosting will stiffen a bit).
Beat the frosting with a handheld electric mixer until smooth, and then frost the cupcakes.
The frosting will soften at room temperature and stiffen in the fridge, so store the cupcakes in an airtight container in the fridge for up to 1 week. Let them sit at room temperature for about 10 minutes before serving.
Net Carbs: 3g per serving (1 frosted cupcake = 1 serving)