In a cup, combine the milk and chocolate syrup and stir well to combine. Set aside.
In the glass from which you will enjoy your frappe, add 4 - 5 ice cubes.
In your frappe shaker, combine the instant coffee, sugar and 1/4 cup water. Shake well until your shaker is almost complete froth.
Pour this froth into your glass over the ice. Pour the chocolate milk which you have made into your shaker and swirl it around to capture the rest of the froth (which may be sticking to the side of your shaker) and pour this into your glass.
Top your glass with more cold water until your glass is almost full.
Pour the creme de menthe into your glass; it will leave a bit of a green colour on your froth. Use a straw or a stir stick to mix gently, being careful not to over mix and destroy your froth.
Enjoy!