Add heavy cream and vanilla to a mixing bowl. Beat until frothy. Add powdered sugar and continue to beat until stiff peaks form. Set whipped cream aside (in the fridge if possible) while you make the milkshakes.
Add ice cream, milk, mint extract, and food coloring to a blender. Cover and blend on high until smooth and creamy.
Pour shamrock shakes into milkshake glasses. Top each shake with whipped cream, sprinkles, and a cherry. Serve immediately.
I used liquid food coloring for this recipe. If you are using gel food color, start with 2 drops, mix, and decide if you need more color. This shake could have a nice mint green color.Serving size depends on the size of your glasses. Nutrition is based on 1/3 of this recipe.