I always prefer my cold coffee beverages made on manual brewing methods. While my take on a Frappe isnt the greek version (cold coffee with lots of foam on top) I use the french definition of frappe (shaken and/or chilled) heres how:
12 grams coffee - ground to about french press
30 ml pouring cream
teaspoon sugar (cold coffee always seems to need sweetning)
milk to fill glass
ice for shaking (in cocktail shaker I prefer a boston shaker as it can give more aeration - mind you I prefer them anyway)
Prepare the aeropress as you normally would. (running sufficient hot water through paper etc). With around 40 mL of hot water brew the coffee using the inverted aeropress method (remove filter/cap and place plunger on the table top - so that when coffee is added it will sit against the black rubber- add the coffee and water and steep for around 45 seconds. Reattach cap/filter and plunge as you normally would). Add sugar to the prepared coffee, pour in cocktail shaker and swirl until sugar is dissolved. Add cream and ice and shake until the container is too cold to touch. Pour into serving glass. Top up with milk.