In a medium saucepan over medium-high heat, whisk together milk, cream, Swerve, and cocoa powder. Bring to a boil and cook one minute, stirring continuously.
Remove from heat and stir in peppermint extract. Sprinkle with xanthan gum and whisk briskly to combine. Let mixture cool at least 10 minutes and then pour into popsicle molds.
Freeze 1 hour, then push wooden sticks partway into popsicles and return to the freezer (wooden sticks are best for staying in the pops when you take them out of the molds). Freeze until solid, about 5 more hours.
To remove from molds, run under hot running water for 30 seconds or so