If you have time; mix the jam sugar and lemon juice with the fruit. Cover and refrigerate for a few hours or overnight.
Place the fruit, jam sugar, and lemon juice in a saucepan over low heat.
Stir occasionally and simmer until the jam thickens and reaches the desired consistency. Test the jam to see if it is ready.
Make sure you have a clean, dry glass jar ready. Pour the hot jam into the jar, screw the lid on tightly, and turn the jar upside down. Leave the jam to cool completely. Once opened, store the jam in the refrigerator and enjoy!