Tip ice cubes out of tray and place into a large freezer bag. Place onto a chopping board and lay a cloth over top. Using a rolling pin, whack the ice with the rolling pin. This will not completely crush the ice but helps the process.
Tip the ice into a blender and pulse slowly. When the ice is almost all crushed, discard all but enough to fill 1/2 to 3/4 each glass.
Add the sugar, coffee and enough milk to top off the glasses to the ice in the blender and whiz until the frappé is slushy and mixed well.
Pour into chilled glasses and top with squirts of cream and a drizzle of chocolate sauce.
Instead of 2 shots fresh espresso, you can substitute with 100ml good quality instant coffee.
If 4 teaspoons granulated sugar is too sweet for you, adjust the sugar to taste.