For the crust: In a medium bowl, combine almond flour, cocoa powder, and 1/4 cup Swerve Confectioners. Stir in the melted butter until a cohesive dough forms.
Press the dough evenly into a 9-inch tart pan with a removable bottom. Bake at 350°F (175°C) for 10-12 minutes, or until lightly firm. Let cool completely on a wire rack.
For the filling: In a medium saucepan, combine heavy whipping cream, xanthan gum (or glucomannan), and 1/2 cup Swerve Confectioners. Heat over medium-low heat, stirring constantly, until the sweeteners are dissolved and the mixture is hot but not boiling.
Remove from heat and add the chopped unsweetened chocolate. Let stand for 5 minutes, then whisk until the chocolate is completely melted and the mixture is smooth and glossy.
Stir in the peppermint extract. Pour the filling into the cooled tart crust. Smooth the top with a spatula.
Refrigerate for at least 4 hours, or until set. For best results, chill overnight.