In a medium-sized saucepan, heat the heavy cream and almond milk over medium heat until it comes to a simmer.
Add the powdered Erythritol and Bulletproof coffee grounds and whisk until they are fully dissolved. Reduce the heat to low and let the mixture steep for 10 to 15 minutes.
In a separate bowl, whisk together the egg yolks, melted butter, vanilla extract, and salt.
Slowly pour the warm cream mixture into the egg yolk mixture, whisking constantly to prevent the eggs from scrambling.
Pour the mixture back into the saucepan and cook over low heat, stirring constantly, until it thickens enough to coat the back of a spoon.
Remove from heat and let the mixture cool to room temperature, then transfer it to a blender or food processor and blend until smooth.
Pour the mixture into an ice cream maker and churn according to the manufacturer's instructions until it reaches a soft-serve consistency.
Transfer the ice cream to a freezer-safe container and freeze for at least 2 hours, or until it has hardened to your desired consistency.
Serve and enjoy!