Russian Berry Custard (Kissel) - cooking recipe

Ingredients

2 cups fresh cranberries, hulled and washed (or strawberries or raspberries)
5 cups water
6 tablespoons sugar (for cranberries, 3 to 4 for strawberries or raspberries)
1/4 cup potato starch

Preparation

Place the berries and 4 cups of the water in a medium size saucepan over medium-high heat. Bring to a boil, then reduce the heat to medium-low and cook until the cranberries pop open or the strawberries or raspberries get somewhat mushy, 10 to 15 minutes.
Allow to cool slightly, then with the back of a spoon, press the berries through a fine-mesh sieve set over a bowl. Be sure to extract as much juice as possible.
Return the sieved berries and liquid to the saucepan. Add the sugar and bring to a boil, stirring over medium heat. Reduce the heat to low and simmer until the sugar is completely dissolved, 2 to 3 minutes.
In a small bowl, dilute the potato starch with the remaining 1 cup water, stirring carefully until there are no lumps. Whisk the mixture into the simmering berry mixture and bring to a boil, stirring vigorously until the mixture thickens.
Remove from the heat and cool, stirring from time to time. Spoon into serving glasses or bowls and refrigerate.