In a saucepan over medium heat on the stove, whisk together the heavy whipping cream, cocoa powder, confectioners sugar substitute, and xanthan gum until well combined.

Heat the mixture to 160 degrees.

In a small bowl, whisk the egg. Slowly add some of the hot mixture, whisking continuously, until the egg is tempered.

Add the egg mixture back to the saucepan and bring the mixture to 165 degrees.

Remove from heat. Stir in the chocolate chips and vanilla extract until completely combined.

Let the mixture rest until it cools to room temperature.

Transfer the mixture to a mixing bowl. Whip until creamy, soft peaks form.

Transfer the mixture to a well-greased loaf pan and place in the freezer to chill for at least 4 hours before serving.