Mix all the ingredients in a blender. If you have an ice cream maker, freeze according to the manufacturer’s directions for about 60% of the time. Take out when still goopy but frozen.
If you do not have an ice cream maker, place in a shallow dish in the freezer and stir every so often until it is at the right consistency.
If you’d like a whipped topping, take the solid cream off the top of a refrigerated can of coconut milk, whip it by hand or mixer and mix in a smidge of sweetener like maple syrup. Top milkshake off with the whipped cream.