In a high speed blender, combine and blend mint leaves, milk, and vanilla, until leaves are pureed and a light green color develops. (note: feel free to add more mint leaves for color and flavor)
Add ice cream; pulse until thoroughly combined
Before adding mint flavoring, taste the shake to see if it’s minty enough for your liking. if not, add a few drops of mint flavoring as needed.
Serve in a chilled glass; top with whipped cream (optional).