In an empty container, mix 5 grams of Agar Agar powder and 2 cup of water, let soak for at least 5 minutes. 30 minutes to 1 hour is prefer.
Add 1/2 cup of sugar, stir to dissolve.
Divide the solution into 2 separate containers, quantity depend on which is your favorite. In my case, the ration is 1:1.
In container 1, add 1/3 cup of coconut milk and 2 tbsp of coffee, stir to mix. This is your coconut solution mixture.
In container 2, just add the remainder coffee and stir.
Bring container 1 to boil and simmer for 15 seconds, then divide and pour into empty cups to create the bottom "ivory" mocha layer. Keep some tablespoon of this mixture on warm to create the top most layer (for decoration purposes)
Bring container 2 to boil and simmer for 15 seconds. By this time, the first ivory layer should be somewhat set, not fully firm but not liquid. Gently pour in the container 2 mixture to create the second dark brown layers. Let sit till set.
To decorate, pour 1-2 tbsp of the ivory leftover mixture over top. Then use a toothpick lightly going over the setting surface back and forward to create the ice-like marble line.
Let the whole thing set and cool down to room temperature. Then you can wrap (to seal in freshness) and place them in refrigerator for 1 hour before serving. The whole cup will be cold enough and feel just like the drink itself from Starbuck