Hull the strawberries and cut the larger ones in half.
Put the berries in a bowl and add 500 grams of sugar. Stir to coat and set aside.
Heat a heavy bottomed pot on low heat and add the oil. Add the chillies and cook for 10 minutes or until perfectly soft.
Add the sugared berries and the lemon zest and juice.
Bring the mixture to a good boil for 20 minutes, stirring occassionally to ensure the jam doesn't stick. Watch that the pot doesn't overflow.
Add the remaining 250 grams of sugar and the sea salt. Stir to combine and continue to cook for another 20 minutes or until setting point.
To sterilise your jam jars, put them in a cold oven and turn the heat to 110 degrees C. Once the oven has reached temperature, leave the jars in for 15 minutes.
To sterilise the jar lids, put them in boiling water in a saucepan and continue to boil for 10 minutes. Place the lids on a clean, unused kitchen towel. The lids and jars must be completely dry before use.
Begin testing the jam for setting point 10 minutes after adding the second batch of sugar. To test, put a drop of jam on to one of the frozen spoons and allow to cool. If, when you drag your fingertip through the jam the path remains clean and doesn't fill with jam again, the jam is at setting point. This may take 30 - 40 minutes.
Carefully pour the jam in to the sterilised jars and seal with the lids. Store in a cool, dry place. Refrigerate after opening.
I have made this jam with frozen strawberries and it turned out wonderfully. Simply thaw the berries and use them, including the juice, as you would fresh berries. Simples.