Place the strawberries in a pan and mash them to a pulp with a potato masher.
Add the maple syrup, lemon zest and lemon juic.
Bring the mixture to the boil over a medium heat, stirring occasionally until the jam thickens. If your berries are very soft and juicy, it could take up to 45 minutes.
To test whether the jam is ready or not, spoon some onto a small spoon and place in the freezer for five minutes. If the jam remains on the spoon when the spoon is turned on it's side it is ready. If not continue to boil and retest in another 6 minutes or so.
Allow to cool then transfer into clean sterilized and store in the fridge and use within 1 week.
Store the rest of the jars in the freezer.