In a medium saucepan over medium heat, combine whipping cream and almond milk. Bring to just a simmer. In a medium bowl, whisk egg yolks with sweetener and salt until well combined.
Slowly whisk about half of the hot cream mixture into the yolks, whisking continuously. Then slowly whisk the yolk/cream mixture back into the saucepan and cook until thickened, 4 to 5 more minutes, whisking continuously.
Remove from heat and whisk in butter and vanilla extract. Sprinkle surface with xanthan gum and whisk vigorously to combine.
Divide mixture among popsicle molds. Freeze one hour, then push wooden sticks three quarters of the way down into the popsicles. Continue to freeze until completely firm, at least another 6 hours.