Add vanilla ice cream, milk, caramel sauce, and green apple to your blender. Blend until smooth. Add the food coloring, if desired, then blend for just a few seconds - until well combined.
Grab a glass and pour a little caramel sauce all the way around the inside of the rim. Pour in the smoothie, then top with whipped cream. Drizzle a little more caramel sauce on top, then enjoy!