Peel and pit the avocados, then slice them into chunks.
Core and slice the green apples.
Wash the fresh mint leaves thoroughly.
Put the avocados, sliced green apples, and mint leaves in a blender.
Add vanilla ice cream to the blender for creaminess (adjust amount as desired).
Mix in 2-3 tablespoons of sweetener based on your taste.
Pour in 2 cups of milk for desired thickness.
Blend on high until smooth.
Taste and adjust sweetness or mintiness if necessary.
Add ice cubes for a colder, thicker shake (optional) and briefly blend again.
Pour the milkshake into glasses.
Optionally, garnish with a slice of green apple or a sprig of fresh mint.