Wash strawberries, remove the stems and cut strawberries in half. Put in the large pot. Cover with sugar and leave it for one hour.
Peel the apple, shred and add it to the strawberries.
Add grated orange peel and juice from orange to strawberries.
Squeeze lemon juice and add to strawberries.
Cook everything on low-medium heat for 2 - 3 hours. Mixing well often.
To check if the jam is ready: leave an empty plate for couple of minutes in the fridge, remove from the fridge, pour hot jam on it. Wait couple seconds when the jam will cool off. This is the consistency of the jam how it will look after cooking. Cook more if the jam is still watery. Or it's up to you how you prefer your jam consistency.
Pour hot water to the mason jars to sterilize them. Leave the water for couple seconds.
Pour jam to the empty jar and close with lid. Put upside down for couple of hours.
When the jam is cooled off, you can store it in the fridge.
*Check the jam, if it's not sweet enough for you, add some more sugar.