1/2 kg [1,1 lb] raspberries
1/2 kg [1,1 lb] blueberries
600 g [1,3 lb] sugar
preservation and or thickening agent
 Clean the berries and rinse them only if necessary. Put the berries in a saucepan along with the sugar.
 Warm up slowly and cook jam over low heat without the lid. Foams well.
 Pour the hot jam into warm, well-cleaned glass jars and put the lids on immediately.