In a medium saucepan, combine the heavy cream, whole milk, and half of the sugar. Heat over medium heat until it just begins to simmer, then remove from heat.
In a separate bowl, whisk together the egg yolks and the remaining sugar until the mixture is pale and slightly thickened.
Slowly add a cup of the warm cream mixture into the egg yolks, whisking constantly to avoid curdling. Then, pour the tempered egg yolk mixture back into the saucepan with the remaining cream mixture.
Cook over medium heat, stirring constantly with a wooden spoon or spatula, until the mixture thickens and coats the back of the spoon (about 170°F or 77°C). Do not let it boil.
Remove from heat and stir in the cannabis-infused butter or oil, vanilla extract, and salt until fully incorporated.
Pour the mixture through a fine mesh strainer (if desired) into a clean bowl to remove any lumps. Cover and chill in the refrigerator for at least 4 hours or overnight.
Pour the chilled mixture into an ice cream maker and churn according to the manufacturer’s instructions, usually about 20-30 minutes, until it reaches a soft-serve consistency.
Transfer the ice cream to an airtight container and freeze for at least 2 hours or until firm.
Scoop and enjoy your cannabis-infused ice cream!