Prepare the berries by removing the husks then wash them in clean water.
Place them in a pot and bring them to boil in about 10 minutes and in low heat.
Add sugar and stir until all the sugar dissolves.
Squeeze lemon to get lemon juice, then add and continue cooking in low heat for another 20 minutes. Stir frequently to make sure the jam doesn't get burned.
Scoop a little jam onto your plate and let it cook then check with your finger or spoon if it wrinkles, then it is ready.
Pour out the jam and put them in sterilized jars, then seal them tightly and let them cool down.
Your jam is ready.
