Place the ice cream, heavy cream, food coloring and mint extract in a blender.
Blend the ice cream, cream, mint extract, and green food coloring until smooth, thick, and creamy. Taste and adjust the mint flavor if needed, then pour into prepared glasses and top as desired.
Serve immediately.
Notes
For the thickest shake, use heavy cream.
Half-and-half gives you a creamy texture with a slightly lighter finish.
Whole milk works for a thinner shake.
Mint extract tastes closest to the classic flavor; peppermint extract will taste sharper.
Gel food coloring gives the brightest green color without thinning the shake.
Start with a small amount of mint extract and add more to taste.
This shake is best served immediately after blending.