Step 1:
Pour the berries into a saucepan, add the sugar, and place over low heat. Bring the berries with sugar to a boil, turn off the fire and let cool down a bit.
Now you need to strain the berries, to separate them from the bones or peels. To do this, you can rub them through a sieve or whip them with a blender, and then pass them through gauze.
When the berry sauce is ready, let it cool to room temperature.