Put a Cuisinart bowl into the freezer to prepare.
In a blender combine half the milk and an avocado, and blend until smooth.
Combine remaining milk, sugar, mint extract and salt in a medium bowl.
Use a hand mixer on low speed and whisk until salt and sugar are dissolved.
Stir in the heavy cream and vanilla, and avocado mixture.
Check color. If you want it to look more like the store bought mint chip, consider adding a little blue and green food coloring. However, the avocado does give it a nice natural greenish yellow coloring.
Cover and refrigerate 1 to 2 hours, or overnight.
Turn on the Cuisinart® ice cream maker and pour the mixture into the frozen freezer bowl and let mix until thickened, about 15 to 20 minutes. It willbe sort and creamy, and melt easily at this stage (see photos)
If a firmer consistency is desired, transfer the ice cream to an airtight container and place in freezer for about 2 hours.
Remove from freezer about 15 minutes before serving.