Sift the cocoa and set it aside. Use a high-speed or immersion blender to mix the coconut milk, sugar, agave, salt, and the espresso, if you’re using it. Add the cocoa and blend the ingredients until they are thoroughly combined. Chill the mixture for at least 1 hour, or overnight.
Add the chilled mixture to your ice cream maker and churn it according to the manufacturer’s instructions. Most machines take 10 to 15 minutes depending on the temperature of the mix, and when it’s finished it should have the consistency of soft serve.
Transfer the ice cream to a large freezer-safe container. Wide and shallow containers work well for mixing, freezing, and scooping later on. Smooth the top, and cover it. Freeze it for at least 5 to 6 hours or until it is firm.
Depending on the temperature of your freezer you may want to set the ice cream out for 5 to 10 minutes to soften it before serving. This ice cream will keep in the freezer for a couple of weeks in an airtight container, but is best when it’s fresh.