Once its done, strain berry mixture using big strainer in a pot, mix agar agar in it very nicely and cook it until it comes to boil. Turn off the heat and allow to cool down to room temperature. Meanwhile, take some ice cubes in a mixing bowl, place another mixing bowl over ice cubes. Add heavy whipping cream and 3 tbsp sugar, whisk using hand mixture at low power setting until the cream reaches stiff peaks. Once done, keep it in to fridge.